Measurement of electron temperatures in the lower ionosphere by detecting the space potential on the langmuir probe characteristic     

B.H. Subbaraya  Satya Prakash  S.P. Gupta  H.S.S. Sinha 《Planetary and Space Science》1974,22(1):180-181

Electron temperatures have been determined at Thumba on Nike Apache flight 10.11 (12 March 1967, 1857 hr IST) by the usual retarding potential analysis and by using an a.c. modulation technique for detecting the space potential on the Langmuir probe characteristic. Simultaneous measurements with the two techniques show that the space potential technique gives temperatures which are related to the temperatures obtained from the retarding potential analysis in a manner remarkably similar to the relations obtained by Booker and Smith as well as by Carlson and Sayers between radar temperatures and d.c. probe temperatures. This result is interesting in view of the fact that radar temperatures have been found to be in good agreement with the temperatures obtained by a.c. modulation techniques on satellite borne probes. The space potential technique is simple, requires limited additional electronics, does not make stringent demands on telemetry and can be easily adopted for rocket borne Langmuir probes.  相似文献   

Mineralogical Characteristics of Iron Ores in Joda and Khondbond Areas in Eastern India with Implications on Beneficiation     

Rajendra Kumar Upadhyay  Akella Satya Venkatesh  Subrata Roy 《Resource Geology》2010,60(2):203-211

Precambrian iron ores of the Singhbhum-North Orissa region occur in eastern India as part of the Iron Ore Group (IOG) within the broad horse-shoe shaped synclinorium. More than 50% of Indian iron ore reserves occur in this region. Massive-hard, flaky-friable, blue dust and lateritic varieties of iron ores are the major ore types, associated with banded hematite, jasper and shales. These ores could have formed as a result of supergene enrichment through gradual but extensive removal of silica, alumina and phosphorus from banded iron formations and ferruginous shale. Attempts for optimal utilization of these resources led to various ore characterization studies using chemical analysis, ore and mineral petrography, XRD analysis, SEM and electron probe micro analysis (EPMA). The ore chemistry indicates that the massive hard ores and blue dust have high iron, low alumina and phosphorus contents. Because of high quality, these ores do not require any specialized beneficiation technique for up-gradation. However, flaky-friable, lateritised and goethitic ores are low in iron, high in alumina and phosphorus contents, requiring specific beneficiation techniques for up-gradation in quality. XRD, SEM and ore microscopic studies of massive hard ores indicate the presence of hematite and goethite, while flaky and lateritic ores show a higher concentration of goethite, kaolinite, gibbsite and hematite. EPMA studies show the presence of adsorbed phosphorous as fine dust in the hard ores. Sink and float studies reveal that most of the gangue minerals are not completely liberated in the case of goethitic and lateritic ores, even at finer fractions.  相似文献   

Longshore grain size trends in the Kakinada-Mulapeta Beach,east coast of India     

D. Satya Prasad  G. V. S. Sarma  M. Subba Rao 《Journal of Earth System Science》1987,96(3):267-278

Shore-normal and shore-parallel variations in grain size statistics of beach sand have been studied over a period of one year along the Kakinada-Mulapeta coast. The southern beaches of this coast have been accretionary while the northern ones erosional since 125 years. The grain size gradings, beach and nearshore processes help in identifying (i) the Groins-fishing harbour beach influenced predominantly by the tidal regime. (ii) the Mulapeta-Vakalapudi beach influenced by refracted wave regime and (iii) the Vakalapudi-fishing harbour beach affected by both wave and tidal regimes at relatively subdued levels.  相似文献   

Retention and release of methane in underground coal workings     

Satya Harpalani  Malcolm J. Mcpherson 《Geotechnical and Geological Engineering》1986,4(3):217-233

Summary During an investigation to study the gas flow characteristics of coal, adsorption and desorption rates of methane from powdered coal samples were measured. From adsorption tests, it was found that the capacity of coal to hold methane varies significantly with gas pressure. For pressures up to 4.14 MPa (600 psi) the amount of gas adsorbed was still rising and monomolecular saturation was not reached. Results of desorption tests were used to test three equations suggested by previous investigators to measure the quantity of desorbed gas. It was confirmed that no single equation would define adequately the complete desorption process. Changes of regime appeared to exist at desorption times of 100 s and, to a lesser extent, 1000 s following the initial release of ambient gas pressure. A hypothesis was advanced that initial flow was inhibited or choked by an efflux of desorbing gas molecules. This was followed by a short transitional period and a longer term regime of free flow with reduced resistance offered by the flow paths.  相似文献   

The P3 kimberlite and P4 lamproite,Wajrakarur kimberlite field,India: mineralogy,and major and minor element compositions of olivines as records of their phenocrystic vs xenocrystic origin     

Shaikh  Azhar M.  Kumar  Satya P.  Patel  Suresh C.  Thakur  Satyajeet S.  Ravi  Subramanian  Behera  Duryadhan 《Mineralogy and Petrology》2018,112(2):609-624

Distinctly different groundmass mineralogy characterise the hypabyssal facies, Mesoproterozoic diamondiferous P3 and P4 intrusions from the Wajrakarur Kimberlite Field, southern India. P3 is an archetypal kimberlite with macrocrysts of olivine and phlogopite set in a groundmass dominated by phlogopite and monticellite with subordinate amounts of serpentine, spinel, perovskite, apatite, calcite and rare baddeleyite. P4 contains mega- and macrocrysts of olivine set in a groundmass dominated by clinopyroxene and phlogopite with subordinate amounts of serpentine, spinel, perovskite, apatite, and occasional gittinsite, and is mineralogically interpreted as an olivine lamproite. Three distinct populations of olivine, phlogopite and clinopyroxene are recognized based on their microtextural and compositional characteristics. The first population includes glimmerite and phlogopite–clinopyroxene nodules, and Mg-rich olivine macrocrysts (Fo 90–93) which are interpreted to be derived from disaggregated mantle xenoliths. The second population comprises macrocrysts of phlogopite and Fe-rich olivine (Fo 81–89) from P3, megacrysts and macrocrysts of Fe-rich olivine (Fo 85–87) from P4 and a rare olivine–clinopyroxene nodule from P4 which are suggested to have a genetic link with the precursor melt of the respective intrusions. The third population represents clearly magmatic minerals such as euhedral phenocrysts of Fe-rich olivine (Fo 85–90) crystallised at mantle depths, and olivine overgrowth rims formed contemporaneously with groundmass minerals at crustal levels. Close spatial association and contemporaneous emplacement of P3 kimberlite and P4 lamproite is explained by a unifying petrogenetic model which involves the interaction of a silica-poor carbonatite melt with differently metasomatised wall rocks in the lithospheric mantle. It is proposed that the metasomatised wall rock for lamproite contained abundant MARID-type and phlogopite-rich metasomatic veins, while that for kimberlite was relatively refractory in nature.

  相似文献   

Delineation of structural features over a part of the Bay of Bengal using total and balanced horizontal derivative techniques     

Satya Narayan  Soumyashree Debasis Sahoo  Ujjawal Kumar  Vipin Kumar Pathak  T. J. Majumdar 《国际地球制图》2017,32(4):351-366

The present study deals with classical problem of edge detection in potential field data over complex tectonic regime for both shallower and deeper sources, simultaneously. Balanced horizontal derivative (BHD) technique is a latest edge detection concept which delineates edges using balancing of amplitude responses for both shallower and deeper sources. The BHD technique has been validated by comparing with total horizontal derivative (THD) technique. Initially, three different synthetic models have been generated with spherical, cylindrical and vertical prismatic objects at different depths and corresponding gravity responses have been enhanced using BHD and THD techniques. Structural features have been delineated from EIGEN6C4 free-air gravity data using THD and BHD techniques over a part of the Bay of Bengal. Major lineaments have been identified in N–S direction followed by those identified along the NE–SW, NW–SE and E–W directions. Both studies of synthetic models and real gravity data reveal that BHD is an advanced technique than THD.  相似文献   

Utilization of high-resolution EGM2008 gravity data for geological exploration over the Singhbhum-Orissa Craton,India     

S.K. Pal  T.J. Majumdar  Vipin Kumar Pathak  Satya Narayan  Ujjawal Kumar  Om Prakash Goswami 《国际地球制图》2016,31(7):783-802

High-resolution EIGEN6C4 and EGM2008 Bouguer gravity data of 2190 degree spherical harmonic over the Singhbhum-Orissa Craton, India, have been generated from the International Centre for Global Earth Models. The Bouguer gravity anomaly difference maps of (i) in situ and EIGEN6C4, (ii) in situ and EGM2008 and iii) EIGEN6C4 and EGM2008 of the study area are compared. It reveals that EIGEN6C4 has lesser systematic error than EGM2008. However, from different profile plots of Bouguer gravity, east–west horizontal derivative and north–south horizontal derivative anomalies of the in situ, EIGEN6C4 and EGM2008, it is observed that most of the signatures of lithounits and geological structural elements are delineated very well by EGM2008 and match 94–98% with those of EIGEN6C4. Further, the Bouguer gravity, east–west horizontal derivative and north–south horizontal derivative anomalies of EGM2008 data over the study area have been used effectively for identifying various lithounits and geological structural elements.  相似文献   

Structure and dynamics of undercurrents in the western boundary current of the Bay of Bengal     

Francis  Pavanathara Augustine  Jithin  Abraham Kaduvathazham  Chatterjee  Abhisek  Mukherjee  Arnab  Shankar  Doraiswamy  Vinayachandran  Puthenveettil Narayanamenon  Ramakrishna  Surireddi Satya Venkata Siva 《Ocean Dynamics》2020,70(3):387-404

Ocean Dynamics - The structure and variability of undercurrents in the East India Coastal Current (EICC), which is the western boundary current system in the Bay of Bengal (BoB), and the mechanisms...  相似文献   

Comparison of high-resolution TRMM-based precipitation products during tropical cyclones in the North Indian Ocean   总被引：3，自引：0，他引：3  

Prakash  Satya  Mahesh  C.  Gairola  R. M.  Pal  P. K. 《Natural Hazards》2012,60(2):689-701

Debris flow moves in the form of surge waves and consists of dozens or even hundreds of surges that are separated in time and space and have a variety of appearances, as exemplified in Jiangjia Gully, China. Observations there indicate that the deposit is made up by superposition of successive surges and deposit of a single surge is in effect a “frozen” surge. Then the study of debris flow is reduced to the study of surge sequence, which leads to a probabilistic picture of debris flow. This study attempts to find the probability distribution of velocity of surge using a huge data set of Jiangjia Gully. Statistics of the data shows that the velocity satisfies the Weibull distribution, which is believed to be universally valid because the distribution parameters vary little between events, with the shape parameter being well related to the average of velocity. It follows that the same distribution applies also to other quantities of debris flow, such as the flow depth and the discharge. Therefore, the distribution can be used to assess the magnitude and overflow range of a potential debris flow, as well as to the parameter calculation for engineering design.  相似文献   

Multivariate statistical approach for assessment of subsidence in Jharia coalfields,India   总被引：1，自引：0，他引：1  

Satya Prakash Sahu  Manish Yadav  Arka Jyoti Das  Amar Prakash  Ajay Kumar 《Arabian Journal of Geosciences》2017,10(8):191

Indian coalfields, one of the major coal producers, are facing serious problem of subsidence now-a-days. This paper attempts to investigate various factors and their influence on magnitude and extent of subsidence. The study was conducted in the Jharia coalfields, India where extraction of thick seams at shallow depths has damaged the ground surface in the form of subsidence. For precise pre-estimation of subsidence, it is therefore necessary to know the contribution of each factor to the occurrence of subsidence. In order to achieve the objectives of this study, several multivariate statistical techniques such as factor analysis (FA), principal component analysis (PCA) and cluster analysis (CA) have been used. Two factors were extracted using FA. Factor 1 and factor 2 account for 42.327% and 24.661% of the variability respectively. Factor 1 represents “natural factor” whereas factor 2 represents “subsidence coefficient”. Spatial variations in regarding susceptibility to the subsidence were determined from hierarchical CA using the linkage distance. Further, the findings of this study would be helpful for prediction of magnitude of subsidence empirically.  相似文献