Spectroscopic identification of the infrared counterpart to GX5-1     

R. M. Bandyopadhyay  T. Shahbaz  P. A. Charles 《Monthly notices of the Royal Astronomical Society》2003,340(3):L13-L16

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Trends in biorobotic autonomous undersea vehicles   总被引：1，自引：0，他引：1  

Bandyopadhyay  P.R. 《Oceanic Engineering, IEEE Journal of》2005,30(1):109-139

The emergence of biorobotic autonomous undersea vehicle (AUV) as a focus for discipline-integrated research in the context of underwater propulsion and maneuvering is considered within the confines of the Biorobotics Program in the Office of Naval Research. The significant advances in three disciplines, namely the biology-inspired high-lift unsteady hydrodynamics, artificial muscle technology and neuroscience-based control, are discussed in an effort to integrate them into viable products. The understanding of the mechanisms of delayed stall, molecular design of artificial muscles and the neural approaches to the actuation of control surfaces is reviewed in the context of devices based on the pectoral fins of fish, while remaining focused on their integrated implementation in biorobotic AUVs. A mechanistic understanding of the balance between cruising and maneuvering in swimming animals and undersea vehicles is given. All aquatic platforms, in both nature and engineering, except during short duration burst speeds that are observed in a few species, appear to lie within the condition where their natural period of oscillation equals the time taken by them to travel the distance of their own lengths. Progress in the development of small underwater experimental biorobotic vehicles is considered where the three aforementioned disciplines are integrated into one novel maneuvering device or propulsor. The potential in maneuvering and silencing is discussed.  相似文献   

Remote sensing of horticultural plantations in Kumarsain tehsil in Shimla district, Himachal Pradesh     

M M Kimothi  M H Kalubarme  Sujay Dutta  Rajendra Thapa  R K Sood 《Journal of the Indian Society of Remote Sensing》1997,25(1):19-26

The favourable agroclimatic conditions for orchards especially apples have increased the acreages in Himachal Pradesh (HP) which has significantly contributed in the growth of state economy. Realizing the importance of horticulture in HP and its changing scenario of the land use/land cover, a study was conducted to identify and map apple and almond plantations in the Kumarsain tehsil of Shimla district using Remote Sensing (RS) techniques. IRS-IB LISS-II False Colour Composite (FCC) diapositives of October 27, March 30 and April 20, 1992 were visually analysed for mapping apple and almond plantations. The results indicate that IRS LISS-II data of April 20 on 1∶50,000 scale was found very useful for identification and mapping of apple and almond plantations in this region. Accuracy of interpretation was also tested on sample basis assuming a binomial distribution for the probability of success/failure of sample points. The overall interpretation accuracy assessed based on 40 sample points was found to be 87 per cent at 90 per cent confidence limits.  相似文献   

Cloud — Aerosol interaction during lightning activity over land and ocean: Precipitation pattern assessment   总被引：1，自引：0，他引：1  

Jayanti Pal  Sutapa Chaudhuri  Arumita Roy Chowdhury  Tanuka Bandyopadhyay 《Asia-Pacific Journal of Atmospheric Sciences》2016,52(3):251-261

The present study attempts to identify the land - ocean contrast in cloud - aerosol relation during lightning and non-lightning days and its effect on subsequent precipitation pattern. The thermal hypothesis in view of Convective Available Potential Energy (CAPE) behind the land - ocean contrast is observed to be insignificant in the present study region. The result shows that the lightning activities are significantly and positively correlated with aerosols over both land and ocean in case of low aerosol loading whereas for high aerosol loading the correlation is significant but, only over land. The study attempts to comprehend the mechanism through which the aerosol and lightning interact using the concept of aerosol indirect effect that includes the study of cloud effective radius, cloud fraction and precipitation rate. The result shows that the increase in lightning activity over ocean might have been caused due to the first aerosol indirect effect, while over land the aerosol indirect effect might have been suppressed due to lightning. Thus, depending on the region and relation between cloud parameters it is observed that the precipitation rate decreases (increases) over ocean during lightning (non-lightning) days. On the other hand during non-lightning days, the precipitation rate decreases over land.  相似文献   

Early Permian transgressive–regressive cycles: Sequence stratigraphic reappraisal of the coal-bearing Barakar Formation,Raniganj Basin,India     

Biplab Bhattacharya  Joyeeta Bhattacharjee  Sandip Bandyopadhyay  Sudipto Banerjee  Kalyan Adhikari 《Journal of Earth System Science》2018,127(2):29

The present research is an attempt to assess the Barakar Formation of the Raniganj Gondwana Basin, India, in the frame of fluvio-marine (estuarine) depositional systems using sequence stratigraphic elements. Analysis of predominant facies associations signify deposition in three sub-environments: (i) a river-dominated bay-head delta zone in the inner estuary, with transition from braided fluvial channels (FA-B1) to tide-affected meandering fluvial channels and flood plains (FA-B2) in the basal part of the succession; (ii) a mixed energy central basin zone, which consists of transitional fluvio-tidal channels (FA-B2), tidal flats, associated with tidal channels and bars (FA-B3) in the middle-upper part of the succession; and (iii) a wave-dominated outer estuary (coastal) zone (FA-B4 with FA-B3) in the upper part of the succession. Stacked progradational (P1, P2)–retrogradational (R1, R2) successions attest to one major base level fluctuation, leading to distinct transgressive–regressive (T–R) cycles with development of initial falling stage systems tract (FSST), followed by lowstand systems tract (LST) and successive transgressive systems tracts (TST-1 and TST-2). Shift in the depositional regime from regressive to transgressive estuarine system in the early Permian Barakar Formation is attributed to change in accommodation space caused by mutual interactions of (i) base level fluctuations in response to climatic amelioration and (ii) basinal tectonisms (exhumation/sagging) related to post-glacial isostatic adjustments in the riftogenic Gondwana basins.  相似文献   

Evaluation　of　Forecast　Performance　of　an　Economical　Explicit　Time　Integration　Scheme　in　a　Limited　Area　Model　over　Indian　Region     

A. Bandyopadhyay  S.S. Singh 《大气科学进展》1994,11(1):101-110

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Comments on the paper by Mack and Robbins relating to a recent theory on the origin of the universal X-ray background     

P. Raychaudhuri  P. Bandyopadhyay 《Astrophysics and Space Science》1973,20(1):43-44

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An 'outside-in' outburst of Aql X–1     

T. Shahbaz  R. M. Bandyopadhyay  P. A. Charles  R. M. Wagner  P. Muhli  P. Hakala  J. Casares  & J. Greenhill 《Monthly notices of the Royal Astronomical Society》1998,300(4):1035-1040

We present optical spectroscopy and optical and infrared photometry of the neutron star soft X-ray transient Aql X–1 during its X-ray outburst of 1997 August. By modelling the X-ray, optical and IR light curves, we find a 3-d delay between the IR and X-ray rise times, analogous to the UV–optical delay seen in dwarf novae outbursts and black hole X-ray transients. We interpret this delay as the signature of an 'outside-in' outburst, in which a thermal instability in the outer disc propagates inward. This outburst is the first of this type definitively identified in a neutron star X-ray transient.  相似文献   

GRO J1744−28, search for the counterpart: infrared photometry and spectroscopy     

A. J. Gosling  R. M. Bandyopadhyay  J. C. A. Miller-Jones  S. A. Farrell 《Monthly notices of the Royal Astronomical Society》2007,380(4):1511-1520

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VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way     

D. Minniti  P.W. Lucas  J.P. Emerson  R.K. Saito  M. Hempel  P. Pietrukowicz  A.V. Ahumada  M.V. Alonso  J. Alonso-Garcia  J.I. Arias  R.M. Bandyopadhyay  R.H. Barbá  B. Barbuy  L.R. Bedin  E. Bica  J. Borissova  L. Bronfman  G. Carraro  M. Catelan  J.J. Clariá  G. Pietrzynski 《New Astronomy》2010,15(5):433-443

We describe the public ESO near-IR variability survey (VVV) scanning the Milky Way bulge and an adjacent section of the mid-plane where star formation activity is high. The survey will take 1929 h of observations with the 4-m VISTA telescope during 5 years (2010–2014), covering ～10⁹ point sources across an area of 520 deg², including 33 known globular clusters and ～350 open clusters. The final product will be a deep near-IR atlas in five passbands (0.9–2.5 μm) and a catalogue of more than 10⁶ variable point sources. Unlike single-epoch surveys that, in most cases, only produce 2-D maps, the VVV variable star survey will enable the construction of a 3-D map of the surveyed region using well-understood distance indicators such as RR Lyrae stars, and Cepheids. It will yield important information on the ages of the populations. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, INTEGRAL, WISE, Fermi LAT, XMM-Newton, GAIA and ALMA for a complete understanding of the variable sources in the inner Milky Way. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its globular cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star forming regions in the disk. The combined variable star catalogues will have important implications for theoretical investigations of pulsation properties of stars.  相似文献