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Chemical, isotopic and amino acid composition of Mukundpura CM2.0(CM1) chondrite: Evidence of parent body aqueous alteration

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Geoscience Frontiers 2019年第2期10卷 495-504页

作者： N.G.Rudraswami a.k.naik R.P.Tripathi N.BhANDari S.G.karapurkar M.Shyam Prasad E.V.S.S.k.Babu U.V.R.Vijaya Sarathi National Institute of Oceanography (Council of Scientific and Industrial Research) 78 BGKT Extension Science and Spirituality Research Institute National Geophysical Research Institute (Council of Scientific and Industrial Research) Indian Institute of Chemical Technology (Council of Scientific and Industrial Research)

The carbonaceous chondrites are intriguing and unique in the sense that they are the only rocks that provide pristine records of the early solar nebular processes. We report here results of a detailed mineralogical, chemical, amino acid and isotopic studies of a recently observed fall at Mukundpura, near Jaipur in Rajasthan, India. Abundance of olivines in this meteorite is low and of serpentine minerals is high. FeO/SiO_2 = 1.05 in its Poorly Characterized Phases(PCP) is similar to that observed in other CM2.0 chondrites. The water content of ～9.8 wt.% is similar to that found in many other CM *** examination of matrix shows that its terrestrial weathering grade is WO but aqueous parent body alteration is high, as reflected in low abundance of identifiable chondrules and abundant remnants of chondrules(～7%). Thus, most of the chondrules formed initially have been significantly altered or dissolved by aqueous alterations on their parent bodies. The measured bulk carbon(2.3%) and nitrogen content and their isotopic(δ^(13)C =-5.5‰, δ^(15)N = 23.6%0) composition is consistent with CM2.0 classification probably bordering CM1. Several amino acids such as Alanine, Serine, Proline, Valine, Threonine,Leucine, Isoleucine, Asparagine and Histamine are present. Tyrosine and Tryptophan may occur in trace amounts which could not be precisely determined. All these data show that Mukundpura chondrite lies at the boundary of CM2.0 and CM1 type carbonaceous chondrites making it one of the most primitive chondrites.

关键词： Carbonaceous chondrite Mukundpura CM Isotope Amino acid

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Suzaku observation of Be / X-ray binary pulsar EXO 2030+375

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Research in Astronomy and Astrophysics 2015年第4期15卷 537-548页

作者： Sachindra naik Gaurava k.Jaisawal Astronomy and Astrophysics Division Physical Research Laboratory

We study the timing and spectral properties of Be/X-ray binary pulsar EXO 2030＋375 using a Suzaku observation taken on 2012 May 23, during a less intense Type I outburst. Pulsations were clearly detected in the X-ray light curves at a barycentric period of 41.2852 s, which suggest that the pulsar is spinning-up. The pulse profiles were found to be peculiar, e.g. unlike those obtained from the earlier Suzaku observation acquired on 2007 May 14. A single-peaked narrow profile at soft X-rays （0.5-10 keV range） changed to a double-peaked broad profile in the 12-55 keV energy range and again reverted back to a smooth single-peaked profile at hard X-rays （55-70 keV range）. The 1.0-100.0 keV broadband spectrum of the pulsar was found to be well described by three continuum models described as （i） a partial covering high energy cut-off power-law model, （ii） a partially absorbed power-law with high- energy exponential rolloff and （iii） a partial covering Negative and Positive power law with EXponential （NPEX） continuum model. Unlike the earlier Suzaku observation during which several low energy emission lines were detected, a weak and narrow Iron ka emission line at 6.4 keV was only present in the pulsar spectrum during the 2012 May outburst. Non-detection of any absorption like feature in the 1-100 keV energy range supports the claim of the absence of the cyclotron resonance scattering feature in EXO 2030＋375 from the earlier Suzaku observation. Pulse-phase resolved spectroscopy revealed the presence of additional dense matter causing the absence of a second peak from the soft X-ray pulse profiles. The details of the results are described in the paper.

关键词： pulsars: individual (EXO 2030+375) -- stars: neutron -- X-rays: stars

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Chaotic Social Group Optimization for Structural Engineering Design Problems

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Journal of Bionic Engineering 2023年第4期20卷 1852-1877页

作者： Anima naik Department of CSE VIITVisakhapatnamAndhra Pradesh530049India

Till now,several novel metaheuristic algorithms are proposed for global *** only specific algorithms have become popular or attracted researchers,who are efficient in solving global optimization problems as well as real-world application *** Social Group Optimization(SGO)algorithm is a new metaheuristic bioinspired algorithm inspired by human social behavior that attracted researchers due to its simplicity and problem-solving *** this study,to deal with the problems of low accuracy and local convergence in SGO,the chaos theory is introduced into the evolutionary process of *** chaotic mapping has certainty,ergodicity,and stochastic property,by replacing the constant value of the self-introspection parameter with chaotic maps,the proposed chaotic social group optimization algorithm increases its convergence rate and resulting *** proposal chaotic SGO is validated through 13 benchmark functions and after that 9 structural engineering design problems have been *** simulated results have been noticed as competent with that of state-of-art algorithms regarding convergence quality and accuracy,which certifies that improved SGO with chaos is valid and feasible.

关键词： Chaos Bionic algorithm Constrained optimization SGO Design problem

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Broad-band spectroscopy of the transient X-ray binary pulsar kS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component

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Research in Astronomy and Astrophysics 2016年第5期16卷 59-68页

作者： Prahlad Epili Sachindra naik Gaurava k.Jaisawal Astronomy and Astrophysics Division Physical Research Laboratory

We present the results obtained from detailed timing and spectral studies of the Be/X-ray binary pulsar kS 1947＋300 during its 2013 giant outburst. We used data from Suzaku observations of the pulsar at two epochs, i.e. on 2013 October 22 （close to the peak of the outburst） and 2013 November 22. X- ray pulsations at - 18.81 s were clearly detected in the light curves obtained from both observations. Pulse periods estimated during the outburst showed that the pulsar was spinning up. The pulse profile was found to be single-peaked up to -10 keV beyond which a sharp peak followed by a dip-like feature appeared at hard X-rays. The dip-like feature has been observed up to -70 keV. The 1-110 keV broad-band spectroscopy of both observations revealed that the best-fit model was comprised of a partially absorbed Negative and Positive power law with EXponential cutoff （NPEX） continuum model along with a blackbody component for the soft X-ray excess and two Gaussian functions at 6.4 and 6.7 keV for emission lines. Both the lines were identified as emission from neutral and He-like iron atoms. To fit the spectra, we included the previously reported cyclotron absorption line at 12.2 keV. From the spin-up rate, the magnetic field of the pulsar was estimated to be -1.2 x 10^12 G and found to be comparable to that obtained from the detection of the cyclotron absorption feature. Pulse-phase resolved spectroscopy revealed the pulsating nature of the soft X-ray excess component in phase with the continuum flux. This confirms that the accretion column and/or accretion stream are the most probable regions of the soft X-ray excess emission in kS1947＋300. The presence of the pulsating soft X-ray excess in phase with continuum emission may be the possible reason for not observing the dip at soft X-rays.

关键词： pulsars: individual (kS 1947+300) -- stars: neutron -- X-rays: binaries

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Does Glacial-Interglacial Transition Affect Sediment Accumulation in Monsoon-Dominated Regions?

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Acta Geologica Sinica(English Edition) 2017年第3期91卷 1079-1094页

作者： Dharmendra Pratap SINGH Rajeev SARASWAT Dinesh k.naik Micropaleontology Laboratory Geological Oceanography DivisionNational Institute of Oceanography

The spatio-temporal changes in sedimentation rate along the continental margin of the monsoon-dominated eastern Arabian Sea during the last 24 kyr have been estimated from a compilation of 58 radiocarbon dated cores, in order to understand the effect of glacial-interglacial variation on sedimentation. The sedimentation rate has been computed for four-time slices, viz. the last glacial maximum, glacial-interglacial transition, early Holocene and late Holocene. We report that the average sedimentation rate in the slope to the abyssal region of the entire eastern Arabian Sea, although higher during the Holocene as compared with that during the last glacial maximum and glacial-interglacial transition, does not significantly vary during all four-time intervals. The sedimentation rate during any particular time interval, however, varies from core to core, thus indicating zonal changes. We report four zones of relatively high sedimentation rate, viz. the northeastern Arabian Sea, the region off the Gulf of khambhat, the region off Goa and Mangalore, and off the southern tip of India. We suggest that a complex interaction of land-ocean-atmospheric processes controlled sedimentation rate in the eastern Arabian Sea during the last 24 kyr in such a way that the average sedimentation rate does not vary significantly, even during highly contrasting climatic conditions.

关键词： Sedimentation rate monsoon glacial Holocene Arabian Sea

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Sm^(3+)induced structural phase transition,spectral,morphological,magnetic,dielectric and impedance properties of Ni_(0.1)Cu_(0.9)Sm_(x)Fe_(2-x)O_(4) nanoferrites

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Journal of Rare Earths 2023年第11期41卷 1736-1745,I0003页

作者： k.Rajashekhar G.Vinod k.Mahesh kumar G.Harikishan Laxman naik J Department of Physics University College of ScienceOsmania UniversityHyderabad500007TelanganaIndia Department of Physics Kamala Institute of Technology and ScienceHuzurabad505468TelanganaIndia Department of Physics CMR College of Engineering&TechnologyHyderabad501401TelanganaIndia

In the present study,rare earth samarium(Sm^(3+))substituted Ni-Cu spinel ferrites with the composition of Ni_(0.1)Cu_(0.9)Sm_(x)Fe_(2-x)O_(4)(0≤x≤0.05 in steps of 0.01)were synthesized by using the citrate induced sol-gel auto combustion *** ferrites'structural,optical,magnetic,and dielectric studies were carried out using X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEM),ultraviolet-visible(UV-vis),a vibrational sample magnetometer(VSM),and an LCR *** pure Ni-Cu ferrite exhibits a tetragonal structure owing to the presence of the John Tellar ion(Cu^(2+)).XRD patterns confirm that the tetragonal structure gradually transforms into the cubic spinel structure with samarium *** nano-scale structures of these ferrites were confirmed by the average crystallite size(10.11-20.99 nm)derived from the X-ray diffraction patterns,and grain size(42.60-83.36 nm)assessed from FESEM *** existence of elements according to their chemical composition was verified by using energy dispersive X-ray(EDX)*** absorption bands(v_(1) and v_(2))detected in FTIR transmission spectra below the wavenumber of 600 cm^(-1)reveal the stretching vibrations of M-O bonds in the spinel structure at tetrahedral and octahedral *** band gap ene rgy obtained from UV absorption reveals the semiconducting nature of the *** high saturation magnetization(M_(s))is noticed at 15 k temperature for x=0.02 composition as 32.98 emu/g,while at 300 k for x=0.01composition as 27.61 emu/*** suggested cation distribution is in good agreement with observed and predicted magnetic moment values at 300 *** expected behavior of ferrites reveals the observed dielectric constant,loss tangent,and ac-conductivity values in the frequency range of 20 Hz-20 ***-Cole plots confirm that the impedance contribution is attributed to grain boundaries.

关键词： Nanoferrites XRD Magnetic properties Dielectric properties Cole-cole plots Rare earths

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Adaptations of phytoplankton in the Indian Ocean sector of the Southern Ocean during austral summer of 1998-2014

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Frontiers of Earth Science 2015年第4期9卷 742-752页

作者： R. k. MISHRA R. k. naik N. ANIL kUMAR ESSO-National Centre for Antarctic and Ocean Research Ministry of Earth Sciences (MoES) Vasco-da-Gama Goa India

This study investigates the effects of light and temperature on the surface water diatoms and chloro- phytes, phytoplankton in the Indian Ocean sector of the Southern Ocean （SO） during the austral summer of 1998- 2014. Significant longitudinal variations in hydrographic and biological parameters were observed at the Sub tropical front （STF）, Sub Antarctic front （SAF） and Polar front （PF） along 56°E-58°E. The concentrations of total surface chlorophyll a （Chl a）, diatoms, and chlorophytes measured by the National Aeronautics Space Agency （NASA） estimated by the Sea-Viewing Wide Field-of- View Sensors （SeaWiFS）, the Moderate Resolution Imaging Spectro Radiometer （MODIS）, and the NASA Ocean Biological Model （NOBM） were used in the study. Variations in the concentration of total Chl a was remarkable amongst the fronts during the study period. The contribution of diatoms to the total concentration of surface Chl a increased towards south from the STF to the PF while it decreased in the case of chlorophytes. The maximum photosynthetically active radiation （PAR） was observed at the STF and it progressively decreased to the PF through the SAF. At the PF region the contribution of diatoms to the total Chl a biomass was ≥80%. On the other hand, the chlorophytes showed a contrary distribution pattern with ≥ 70% of the total Chl a biomass recorded at the STF which gradually decreased towards the PF, mainly attributed to the temperate adaptation. This clearly reveals that the trend of diatoms increased at the STF and decreased at the SAF and the PF. Further, the trend of chlorophytes was increased at the STF, SAF and PF with a shift in the community in the frontal system of the Indian Ocean sector of the SO.

关键词： chlorophyll a diatoms chlorophytes SST,PAR Southern Ocean

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Analysis and Comparison of Two Wireless Battery Charger Arrangements for Electric Vehicles

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Chinese Journal of Electrical Engineering 2015年第1期1卷 50-57页

作者： Giuseppe Buja Rupesh k.Jha Manuele Bertoluzzo Mude k.naik Department of Industrial Engineering University of PadovaPadovaItaly Department of Electrical Engineering AVVP UniversityBengaluruIndia

The paper deals with wireless battery chargers(WBCs)for plug-in electric vehicles(PEVs)and analyzes two arrangements for the receiver of a series-series resonant *** first arrangement charges the PEV battery in a straightforward manner through a diode *** second arrangement charges the PEV battery through the cascade of a diode rectifier and a chopper whose input voltage is kept *** of merit of WBCs such as efficiency and sizing factor of both the power source and the transmitter/receiver coils are ***,they are discussed and compared with reference to the case study of WBC for an electric city car.A proposal to optimize the efficiency of the second arrangement by a suitable selection of the chopper input voltage is *** on the efficiency of the two arrangements are included to support the theoretical results.

关键词： EV battery charging wireless charging charging arrangement

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Modeling the mechanics of calcium regulation in T lymphocyte:A finite element method approach

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International Journal of Biomathematics 2020年第5期13卷 149-169页

作者： Parvaiz Ahmad naik School of Mathematics and Statistics Xi'an Jiaotong Unirersity Xi'an Shaanxi 710049P.R.China

Changes in cellular Ca2+concentration control a variety of physiological activities including hormone and neurotransmitter release,muscular contraction,synaptic plas-ticity,ionic channel permeability,apoptosis,enzyme activity,gene transcription and reproduction ***-temporal Ca2+dynamics due to Ca2 t release,buffering and re-uptaking plays a central role in studying the Ca2+regulation in T *** most cases,Ca2+has its major signaling function when it is elevated in the cytosolic *** this paper,a two-dimensional mathematical model to study spatiotemporal variations of intracellular Ca2+concentration in T lymphocyte cell is proposed and *** cell is assumed to be a circular shaped geomnetrical domain for the representation of properties of Ca2+dynamics within the cell includ-ing important ***2+binding proteins for the dynamics of Ca2+are itself buffer and other physiological parameters located in Ca2+*** model incorpo-rates the important biophysical processes like difusion,reaction,voltage gated Ca2+channel,leak from endoplasmic reticulum(ER),efflux from cytosol to ER via sarco ER Ca2+adenosine triphosphate(SERCA)pumps,buffers and Na+/Ca2+*** proposed mathematical model is solved using a finite difference method and the finite element *** initial and boundary conditions are incorporated in the model based on biophysical conditions of the *** simulations in MAT-LAB R2019b are employed to investigate mathematical models of reaction-diffusion *** effect of source,buffer,Nat/Ca2+exchanger,*** spatial and tempo-ral patterns of Ca2+in T lymphocyte has been studied with the help of numerical *** the obtained results,it is observed that,the coordinated combination of the incor-porated parameters plays a significant role in Ca2+regulation in T *** leak and voltage-gated Ca2+channel provides the necessary Ca2+to the cell when required for its proper

关键词： Nat/Ca2+exchanger SERCA purmp ER leak voltage gated Ca2+channel buffers diffusion coefficient reaction-diffusion equations Ritz method and variational form

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Battery Charging Method for Electric Vehicles:From Wired to On-Road Wireless Charging

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Chinese Journal of Electrical Engineering 2018年第4期4卷 1-15页

作者： kishore naik Mude Solace Power Inc. 1118 Topsail road Mount PearlNewfoundland and LabradorA1N5E7Canada

Recent fossil fuel shortages and global warming related problems have caused a substantial shift from internal combustion engine vehicles towards *** paper explores the thorough review of battery charging infrastructure from wired connection to on-road wireless charging for an *** initial part of the paper deals with the wired charging and its power electronics *** later portion deals with the wireless charging where both static and On-Road types are ***,various aspects of wireless power transfer are also *** Market scenario and future growth prospects are reviewed and presented in last section of the paper.

关键词： Wired charging static WPT on-road WPT

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