Artificial modification of ionosphericE-layer by high power radio transmitters     

S. S. De  S. K. Adhikari  J. Bandyopadhyay  S. K. Dubey  S. Bandyopadhyay  A. C. Sen 《Pure and Applied Geophysics》1990,132(4):803-810

Some anomalous TV receptions in India on band I have been interpreted as being propagated viaF-layer artificially modified by high power broadcast transmitters. In this paper, the possibility of VHF communication by artificially modifiedE-layer is discussed. The presented theoretical analysis shows that high-power broadcast trasmitters can produce substantial changes in temperature and ionisation in theE-layer. The rate of energy transfer from the wave to the medium particles has also been computed. Model calculations are made for a transmitter located near Calcutta. The possibility of the extra-ionisation producing field-aligned structures to support VHF communication is discussed.  相似文献   

The Effects of Solar Eclipse of August 1, 2008 on Earth’s Atmospheric Parameters     

Syam Sundar De  B. K. De  B. Bandyopadhyay  B. K. Sarkar  Suman Paul  D. K. Haldar  S. Barui  Asim Datta  Syam Sundar Paul  Nikhilesh Paul 《Pure and Applied Geophysics》2010,167(10):1273-1279

Several experiments were undertaken at Kolkata (latitude: 22°34′N, longitude: 88°30′E) on the solar eclipse day of August 1, 2008 to observe the effects of the solar eclipse on Fair Weather Field (FWF) and VLF amplitude and phase. The experimental results presented here show significant deviations of the observed parameters from their normal values, as they are determined by the average of the records obtained on 5 days adjacent to the day of the solar eclipse.  相似文献   

Geologic weathering and its implications on the age of the sphinx     

K. Lal Gauri  John J. Sinai  Jayanta K. Bandyopadhyay 《Geoarchaeology》1995,10(2):119-133

The Great Sphinx of Giza is considered by Egyptologists to have been excavated by the Pharaoh Kephren nearly 4500 years ago. Schoch and West (1991) have suggested that the Sphinx is much older, based primarily upon the rounded profile of the strata of the Sphinx thorax and the deep channels present in the walls surrounding the Sphinx ditch. These features, according to them, are due to “precipitation-induced weathering” formed when the Sahara still experienced a humid climate at least 7000 years ago. In this article we show how weathering in an arid environment can produce the rounded profile given the gradual change in lithology of the alternating hard and soft limestone strata. We show further that the channels are actually the pre-Pliocene karst features formed by underground water and exposed due to the excavation of the Sphinx ditch. We propose therefore that, for now, the Sphinx may still be regarded as of pharaonic origin. © 1995 John Wiley & Sons, Inc.  相似文献   

Air Dispersion Modeling: Foundations and Application By Alex de Visscher, John Wiley & Sons, Hoboken,NJ, USA 2013 ISBN: 978‐1‐118‐07859‐4 € 119.00          下载免费PDF全文

Amitava Bandyopadhyay 《洁净——土壤、空气、水》2015,43(10):1441-1441

  相似文献   

Bioprocessing Technologies in Biorefinery for Sustainable Production of Fuels,Chemicals, and Polymers,Edited by: Shang‐Tian Yang,Hesham El‐Ensashy & Nuttha Thongchul, 2nd Edition, John Wiley & Sons, Hoboken,NJ, USA 2013, ISBN: 978‐0‐470‐54195‐1, € 135.00.          下载免费PDF全文

Amitava Bandyopadhyay 《洁净——土壤、空气、水》2015,43(11):1556-1557

  相似文献   

Dense matter in strong gravitational field of neutron star     

Sajad A. Bhat  Debades Bandyopadhyay 《Journal of Astrophysics and Astronomy》2018,39(1):18

Mass, radius and moment of inertia are direct probes of compositions and Equation of State (EoS) of dense matter in neutron star interior. These are computed for novel phases of dense matter involving hyperons and antikaon condensate and their observable consequences are discussed in this article. Furthermore, the relationship between moment of inertia and quadrupole moment is also explored.  相似文献   

Assessing the oscillation of channel geometry and meander migration cardinality of Bhagirathi River,West Bengal,India     

Bag  Rakhohori  Mondal  Ismail  Bandyopadhyay  Jatisankar 《地理学报(英文版)》2019,29(4):613-634

Journal of Geographical Sciences - Lateral migration of the Bhagirathi River temporally creates unavoidable geomorphic hazards in West Bengal, India. The Bhagirathi River flows SW for ~67.30 km...  相似文献   

Intertidal foraminifera in the macro-tidal estuaries of the Gulf of Cambay: Implications for interpreting sea-level change in palaeo-estuaries     

Anupam Ghosh  Sourav Saha  Pratul Kumar Saraswati  Santanu Banerjee  Stuart Burley   《Marine and Petroleum Geology》2009,26(8):1592-1599

The Gulf of Cambay is a macro-tidal estuarine embayment lying in an active monsoon zone characterized by a high annual sediment load. The present study examines the distribution of foraminifera in the Narmada and Tapti estuaries of the Gulf in order to use these as analogues for the study of palaeo-macro-tidal estuarine environments and as a means of recording the extent of sea-level change in estuarine settings. Foraminifera are widely distributed in sand flats, mud flats and marshes at the mouths of the estuaries. The overall foraminiferal assemblage is low diversity, comprising epifaunal and infaunal taxa dominated by Ammonia, Murrayinella, Haynesina, Quinqueloculina, Nonion, Cibicides, Cibicidoides, Elphidium, Trochammina and Miliammina. The triserial planktonic foraminifer Gallitellia vivans, an indicator of stressed and up-welling areas, is also recorded in the intertidal sediments of the estuaries. These foraminifera are carried into estuaries up to 50 km up the river mouths by the strong tidal currents in the bay. Three biofacies are recognized: Trochammina–Miliammina biofacies (high marsh); Murrayinella-Haynesina biofacies (low marsh and mud flats) and Ammonia-Elphidium-Quinqueloculina biofacies (shallow marine).  相似文献   

Time-dependent diffusive interactions between dark matter and dark energy in the context of k-essence cosmology     

Abhijit Bandyopadhyay  Anirban Chatterjee 《天文和天体物理学研究(英文版)》2021,(1):15-24

We investigated the scenario of time-dependent diffusive interaction between dark matter and dark energy and showed that such a model can be accommodated within the observations of luminosity distanceredshift data in Supernova la(SN la)observations.We obtain constraints on different relevant parameters of this model from the observational data.We consider a homogeneous scalar field(t)driven by a k-essence Lagrangian of the form L=V(φ)F(X)with constant potential V(φ)=V,to describe the dynamics of dark energy in this model.Using the temporal behaviour of the FRW scale factor,the equation of state and total energy density of the dark fluid,extracted from the analysis of SN la(JLA)data,we have obtained the time-dependence of the k-essence scalar field and also reconstructed the form of the function F(X)in the k-essence Lagrangian.  相似文献   

Density Measurements of Shock Compressed Matter Using Short Pulse Laser Diagnostics     

M. Koenig  A. Ravasio  A. Benuzzi-Mounaix  B. Loupias  N. Ozaki  M. Borghesi  C. Cecchetti  D. Batani  R. Dezulian  S. Lepape  P. Patel  H. S. Park  D. Hicks  A. Mckinnon  T. Boehly  A. Schiavi  E. Henry  M. Notley  R. Clark  S. Bandyopadhyay 《Astrophysics and Space Science》2007,307(1-3):257-261

In this paper, experimental results on X-ray and proton radiography of shock compressed matter are presented. It has been performed at the Rutherford Appleton Laboratory (RAL) using three long pulse beams to generate a shock wave in a multi-layer foil and a short pulse beam to create either an X-ray or protons source for a transverse radiography. Depending on the probe material (aluminium or carbon foam) a Molybdenum Kα source or a proton beam are used. Density data of the shocked aluminium, in the multimagabar regime are presented.  相似文献