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A New Report of serpentinites from Northern Central Indian Ridge(at 6°s)—An Implication for Hydrothermal Activity

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Acta Geologica sinica(English Edition) 2008年第6期82卷 1213-1222页

作者： Dwijesh RAY Ranadip BANERJEE sridhar D.IYER subir MUKHOPADHYAY Geological Oceanography Division National Institute of OceanographyGoa 403004India Department of Geological sciences Jadavpur UniversityKolkata 700 032India

serpentinites from the inside corner high （6°38.5′s/68°19.34′E） from the Northern Central Indian Ridge （NCIR） are comprised mainly of high Mg-rich lizardite and chrysotile pseudomorphs with varying morphologies. ＇Mesh rim＇, ＇window＇, ＇hourglass＇ and ＇bastite＇ are the most common textures displayed by both chrysotile and lizardite. Numerous chrysotile veins in association with cross cutting magnetite veins indicate an advanced stage of serpentinisation. The relatively high abundance of chrysotile and lizardite suggest their close association and formation at a temperature below 250℃. Abundant ＇mesh rim＇ and ＇bastite＇ texture and variegated matrix reveal that the present serpentinites might have formed due to the interaction of harzburgite and seawater. Positive Eu anomaly （Eu/Eu^＊ up to ＋3.38）, higher La/sm （up to 4.40） and Nb/La （up to 6.34） ratios suggest substantial hydrothermal influence during the formation of the serpentinites.

关键词： serpentinite serpentinisation hydrothermal alteration

Performance evaluation of neural network TEC forecasting models over equatorial low-latitude Indian GNss station

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Geodesy and Geodynamics 2020年第3期11卷 192-201页

作者： G.sivavaraprasad V.s.Deepika D.sreenivasa Rao M.Ravi Kumar M.sridhar Department of Electronics and Communication Engineering Koneru Lakshamaiah Education FoundationK L Deemed to be UniversityVaddeswaramGuntur District522502Andhra PradeshIndia

Global Positioning system(GPs)services could be improved through prediction of ionospheric delays for satellite-based radio *** respect to latitude,longitude,local time,season,solar cycle and geomagnetic activity the Total Electron Content(TEC)have significant variations in both time and *** temporal and spatial TEC variations driven by interplanetary space weather conditions such as solar and geomagnetic activities can degrade the communication and navigation links of ***,in this paper,performance of TEC forecasting models based on Neural Networks(NN)have been evaluated to forecast(1-h ahead)ionospheric TEC over equatorial low latitude Bengaluru e12:97+N;77:59+ET,Global Navigation satellite system(GNss)station,*** VTEC data is collected for 2009 e2016(8 years)during current 24 th solar *** input space for the NN models comprise the solar Extreme UV flux,F10.7 proxy,a geomagnetic planetary A index(AP)index,sunspot number(ssN),disturbance storm time(DsT)index,solar wind speed(Vsw),solar wind proton density(Np),Interplanetary Magnetic Field(IMF Bz).The performance of NN based TEC forecast models and International Reference Ionosphere,IRI-2016 global TEC model has evaluated during testing period,*** NN based model driven by all the inputs,which is a NN unified model(NNunq)has shown better accuracy with Mean Absolute Error(MAE)of 3.15 TECU,Mean square Deviation(MsD)of 16.8 and Mean Absolute Percentage Error(MAPE)of 19.8%and is 1 e25%more accurate than the other NN based TEC forecast models(NN1,NN2 and NN3)and IRI-2016 *** model has less Root Mean square Error(RMsE)value 3.8 TECU and highest goodness-of-fit(R2)with *** experimental results imply that NNunq/NN1 model forecasts ionospheric TEC accurately across equatorial low-latitude GNss station and IRI-2016 model performance is necessarily improved as its forecast accuracy is limited to 69 e70%.

关键词： Global Positioning system(GPs) Global navigation satellite systems(GNss) Total electron content(TEC) International reference ionosphere(IRI) Neural networks

Occurrence and Emplacement of Chromite Ores in sindhudurg District,Maharashtra,India

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Acta Geologica sinica(English Edition) 2010年第3期84卷 515-527页

作者： sridhar D.IYER Elapavalooru V.s.s.K.BABU Premchand G.MIsLANKAR Anup R.GUJAR Navso V.AMBRE Victor J.LOVEsON National Institute of Oceanography Council of Scientific and Industrial ResearchDona PaulaGoa 403004India National Geophysical Research Institute Council of Scientific and Industrial ResearchHyderabad 500007India Central Institute of Mining and Fuel Research Council of Scientific and Industrial ResearchDhanbad 828108India

In the present study,we present the occurrence and emplacement of chromite ore deposits from two abandoned mines（Kankavali[Janoli]and Wagda） in the sindhudurg district of Maharashtra,*** ores,that occurred as lenses and are associated with metamorphic and ultrabasic rocks,consist of octahedral grains of chromite,while clinochlore is present between the interstices of these *** Kankavali（Janoli） and Wagda ores revealed a dominance of Cr_2O_3 followed by FeO and variable proportions of A1_2O_3,MgO,and siO_*** former deposits have a slightly higher Cr_2O_3（average 52 wt%） and FeO（～18 wt%） than those from Wagda（Cr_2O_3～50 wt%,FeO～25 wt%）.The similar Cr~# values（0.73 for Kankavali[Janoli],0.74 for Wagda） correspond to those reported for typical podiform-type chromite *** suggest that the ores were emplaced as phacoliths in folded outcrops with a steep easterly dip and a northwest-southeast *** postulate the continuation of the fold structure from Janoli to Wagda（～4.5 km apart） and the probable （sporadic） occurrence of chromite along this *** possibility of the contribution of chromite grains from these areas to the coastal placer deposits cannot be ruled out.

关键词： chromite podiform formation placer sindhudurg India

Glass and Mineral Chemistry of Northern Central Indian Ridge Basalts:Compositional Diversity and Petrogenetic significance

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Acta Geologica sinica(English Edition) 2009年第6期83卷 1122-1135页

作者： Dwijesh RAY Ranadip BANERJEE sridhar D IYER Basavaraju BAsAVALINGU subir MUKHOPADHYAY4 National Centre for Antarctic and Ocean Research National Institute of Oceanography CSIR Department of studies in Geology University of Mysore Department of Geological sciences Jadavpur University

The glass and mineral chemistry of basaits examined from the northern central Indian ridge （NCIR） provides an insight into magma genesis around the vicinity of two transform faults： Vityaz （VT） and Vema （VM）. The studied mid-ocean ridge basalts （MORBs） from the outer ridge flank （VT area） and a near-ridge seamount （VM area） reveal that they are moderately phyric plagioclase basalts composed of plagioclase （phenocryst [An60-90] and groundmass [An35-79]）, olivine （Fo81-88）, diopside （Wo45-51, En25-37, Fs14-24）, and titanomagnetite （FeOt -63.75 wt% and TiO2 -22.69 wt%）. The wholerock composition of these basalts has similar Mg# [mole Mg/mole（Mg＋Fe2＋）] （VT basalt： -0.56-0.58; VM basalt： -0.57）, but differ in their total alkali content （VT basalt： -2.65; VM basalt： -3.24）. The bulk composition of the magma was gradually depleted in MgO and enriched in FeOt, TiO2, P2O5, and Na2O with progressive fractionation, the basalts were gradually enriched in Y and Zr and depleted in Ni and Cr. In addition, the ∑REE of magma also increased with fractionation, without any change in the （La/ Yb）N value. Glass from the VM seamount shows more fractionated characters （Mg#： 0.56-0.57） compared to the outer ridge flank lava of the VT area （Mg#： 0.63-0.65）. This study concludes that present basalts experienced low-pressure crystallization at a relatively shallow depth. The geochemical changes in the NCIR magmas resulted from fractional crystallization at a shallow depth. As a consequence, spinel was the first mineral to crystallize at a pressure 〉10 kbar, followed by Fe-rich olivine at 〈10 kbar pressure.

关键词： mineral chemistry fractional crystallization petrogenesis northern central Indian ridge

Impact of poly chlorinated biphenyl (Aroclor 1254) and vitamin C on antioxidant system of rat ventral prostate

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Asian Journal of Andrology 2004年第1期6卷 19-22页

作者： M. sridhar P. Venkataraman s. Dhanammal A. Arunkumar M.M. Aruldhas N. srinivasan J. Arunakaran Department of Endocrinology Dr. ALM Post Graduate Institute of Basic Medical Sciences University of MadrasTaramani Chennai 600 113 India

Aim: To evaluate the effect of polychlorinated biphenyls (PCB) and vitamin C on ventral prostatic antioxidant system in adult male rats. Methods: A group of 20 adult male rats were administered ip Aroclor 1254 in corn oil at a dose of 2 mg·kg-1·day-1 for 30 days. Ten control rats were administered only the vehicle. After 30 days the treated rats were divided at random into 2 sub-groups of 10 animals each. One sub-group received vitamin C at a dose of 500 mg·kg-1·day-1 for 10 days. The other group was maintained as Aroclor 1254 control. Twenty-four hours after the last treatment the rats were killed by decapitation. Ventral prostatic homogenate was prepared and used for the estimation of enzymatic antioxidants, including superoxide dismutase (sOD), catalase (CAT) and glutathione-s-transferase (GsT) and hydrogen peroxide (H2O2), lipid peroxidation (LPO) and prostatic acid phosphatase. The serum levels of total T3, total T4, TsH, testosterone and estradiol were also assayed. Results: The body weight and ventral prostatic weight were reduced in PCB treated rats. The activities of sOD, CAT, GsT and acid phosphatase were decreased while the levels of H2O2 and lipid peroxidation were increased in the ventral prostate of PCB treated rats. Administration of vitamin C restored these parameters. serum levels of thyroid hormones, estradiol and testosterone were decreased in PCB treated animals. Administration of vitamin C restored the thyroid hormone levels. Conclusion: PCB induces oxidative stress and decreases the antioxidant enzymes in the ventral prostate of adult male rats; the effects could be reversed by the administration of vitamin C.

关键词： polychlorinated biphenyls Aroclor 1254 ventral prostate antioxidants lipid peroxidation thyroid hormone vitamin C

Current Concepts in the Diagnosis and Management of Pulmonary Embolism

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International Journal of Clinical Medicine 2021年第3期12卷 115-129页

作者： sridhar Kasturi sunshine Heart Institute Secunderabad Telangana Hyderabad India

Acute pulmonary embolism (PE) is one of the most common causes of cardiovascular death. Most often acute PE is associated with under diagnosis, misdiagnosis and delay in diagnosis and management leading to high morbidity and mortality. PE outcomes will improve with proper evaluation of clinical symptoms and signs, relevant diagnostic tests, identifying high-risk patients suitable for early re-perfusion with I.V. or catheter-directed thrombolytic therapy or surgical embolectomy and in some cases additional use of mechanical circulatory support. During clinical evaluation modified Geneva score, Well’s score, and simplified pulmonary embolism severity index (sPEsI) scores are useful in assessing PE and its adverse outcomes. Hestia criteria are useful in identifying suitable for outpatient management of PE. Long-term management of PE involves identifying patients prone for recurrence and CTPE with appropriate long-term prophylaxis using oral anticoagulants.

关键词： Pulmonary Embolism Management of PE

A Petrogenetic Model of Basalts from the Northern Central Indian Ridge:3-11°s

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Acta Geologica sinica(English Edition) 2007年第1期81卷 99-112页

作者： Dwijesh RAY sridhar D. IYER Ranadip BANERJEE saumitra MIsRA M. WIDDOWsON Geological Oceanography Division National Institute of Oceanography Goa-403 004 India Department of Geology and Geophysics Indian Institute of Technology Kharagpur-721 302 India Department of Earth sciences Open University Milton Keynes MK7 6AA U.K.

Mid-Ocean Ridge Basalts （MORB） from the Northern Central Indian Ridge （NCIR） were recovered between latitudes 3° and 11° s and are olivine tholeiite with higher abundances of K and Rb. They are of typical transitional MORB （T-MORB） variety and appear to have been generated from an enriched-mantle peridotite source. The primitive NCIR MORBs having Mg^# 〉 0.68 are the product of partial melting at an estimated pressure of - 1 GPa. It is inferred that the magma was subsequently modified at a pressure 〉 1 GPa by crystal fractionation and spinel was the first mineral to crystallize followed by separation of relatively Fe-rich olivine with subsequent decrease in pressure. During progressive fractionation at lower pressure （between 1-0.5 GPa）, the bulk composition of the magma became systematically depleted in MgO, and enriched in ∑FeO, TiO2, P2Os and Na20. There was, however, limited gradual depletion in Al2O3 and CaO and concomitant enrichment in K20. With the progressive fractionation these basalts became gradually enriched in V, Co, Y, Zr and to some extent in sr, and depleted in Ni and Cro In addition, the T_JtEE of the magma also increased with fractionation, without any change in （La/Yb）n value.

关键词： MORB NCIR geochemistry petrogenesis Indian Ocean mid-ocean ridge

Mechanical behavior of organo-modified Indian bentonite nanoclay fiber-reinforced plastic nanocomposites

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Frontiers of Materials science 2013年第4期7卷 396-404页

作者： N. RAGHAVENDRA H. N. NARAsIMHA MURTHY M. KRIsHNA K. R. VIsHNU MAHEsH R. sridhar s. FIRDOsH G. ANGADI s. C. sHARMA Center for Manufacturing and Research Technology Utilization R. V. College Campus Bangalore 560059 Karnataka India Department of Mechanical Engineering R. V. College of Engineering Bangalore 560059 Karnataka India Department of Chemistry ACS College of Engineering Bangalore 560074 Karnataka India Tumkur University Tumkur 572103 Karnataka India

The aim of the research was to examine the influence of organo-modified Indian bentonite （IB） nanoclay dispersed in vinyisster on the mechanical properties of nanoclaylvinylesterlglass nanocomposRes. Nanoclay was organically modified using cationic surfactant hexadecyltrimethylammonium bromide （HDTMA-Br） by cation exchange method and dispersed in vinylester using ultrasonication and twin screw extrusion. XRD of nanoclaylvinylester revealed exfoliaUon at 4 wt.% nanoclay indicating uniform dispersion in the polymer. DsC results showed improvement in glass transition temperature by 22.3% in 4 wt.% nanoclaylvinylester/glass when compared with that of vinylester/glass. Nanoclay/vinylester/glass with 4 wt,% nanoclay showed 29.23%, 23.84% and 60.87% improvement in ultimate tensile strength （UTs）, fiexural strength （Fs） and interlaminar shear strength （ILss） respectively when compared with those of vinylester! glass. The mode of tensile failure examined by sEM showed no agglomeration of nanoclay in 4 wt.% nanoclayNinylester/glass specimens.

关键词： Indian bentonite (IB) ultrasonication twin-screw extrusion mechanical property

Novel color center platforms enabling fundamental scientific discovery

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InfoMat 2021年第8期3卷 869-890页

作者： Victoria A.Norman sridhar Majety Zhipan Wang William H.Casey Nicholas Curro Marina Radulaski Department of Electrical and Computer Engineering University of California at DavisDavisCalifornia Department of Physics University of California at DavisDavisCalifornia Department of Chemistry Department of Earth and Planetary SciencesUniversity of California at DavisDavisCalifornia

Color centers are versatile systems that generate quantum light,sense magnetic fields and produce spin-photon *** review how these properties have pushed the limits of fundamental knowledge in a variety of scientific disciplines,from rejecting local-realistic theories to sensing superconducting phase *** the light of recent progress in material processing and device fabrication,we identify new opportunities for interdisciplinary fundamental discoveries in physics and geochemistry.

关键词： color centers magnetometry nano-sensing photonics quantum information