Logarithmic Entropy-Corrected Holographic Dark Energy in Hořava-Lifshitz cosmology with Granda-Oliveros cut-off     

Antonio Pasqua  Surajit Chattopadhyay 《Astrophysics and Space Science》2013,348(2):541-551

In this work, we studied the Logarithmic Entropy-Corrected Holographic Dark Energy (LECHDE) model in a spatially non-flat universe and in the framework of Ho?ava-Lifshitz cosmology. As infrared cutoff of the system we considered the cut-off recently proposed by Granda and Oliveros which contains two terms, one proportional to H ² and one to $\dot{H}$ . For the two cases containing non-interacting and interacting Dark Energy (DE) and Dark Matter (DM), we obtained the exact differential equation that determines the evolution of the density parameter. Moreover, we derived the expressions of the deceleration parameter q and, using a parametrization of the equation of state (EoS) parameter ω _D of our model as ω _D (z)=ω ₀+ω ₁ z, we derived both the expressions of ω ₀ and ω ₁ for both non-interacting and interacting cases. All derivations made in this work are done in small redshift approximation and for low redshift expansion of the equation of state (EoS) parameter.  相似文献   

Reconstruction of f(T) gravity from the Holographic Dark Energy     

Surajit Chattopadhyay  Antonio Pasqua 《Astrophysics and Space Science》2013,344(1):269-274

Among different candidates to play the role of Dark Energy (DE), modified gravity has emerged as offering a possible unification of Dark Matter (DM) and DE. The purpose of this work is to develop a reconstruction scheme for the modified gravity with f(T) action using holographic energy density. In the framework of the said modified gravity we have considered the equation of state of the Holographic DE (HDE) density. Subsequently we have developed a reconstruction scheme for modified gravity with f(T) action. Finally we have obtained a modified gravity action consistent with the HDE scenario.  相似文献   

New Agegraphic Dark Energy model in chameleon Brans-Dicke cosmology for different forms of the scale factor     

Antonio Pasqua  Surajit Chattopadhyay 《Astrophysics and Space Science》2013,348(1):283-291

In this work, we study the New Agegraphic Dark Energy (NADE) model (which contains the conformal time η as infrared cut-off) in the framework of Brans-Dicke cosmology with chameleon scalar field which is non-minimally coupled to the matter field. Considering interacting Dark Energy and Dark Matter (DM), we calculate some relevant cosmological parameters, i.e. the equation of state (EoS) parameter, the deceleration parameter q and the evolution of the energy density parameter $\varOmega_{D}'$ for different forms of scale factors, i.e. the power-law, the emergent, the intermediate and the logamediate ones, which leads to different expressions of η.  相似文献   

Detection of 2009 Leonid,Perseid and Geminid Meteor Showers through its effects on Transmitted VLF Signals     

S. S. De  B. K. De  Pinaki Pal  B. Bandyopadhyay  S. Barui  D. K. Haldar  Suman Paul  Minu Sanfui  Goutami Chattopadhyay 《Astrophysics and Space Science》2011,332(2):353-357

The detection of 2009 Leonid, Perseid and Geminid meteor showers over Agartala, Tripura, India (Lat: 23.0° N, Long: 91.4° E) will be reported here by using two VLF receivers tuned to subionospheric transmitted VLF signals at the frequency 16.4 kHz from Aldra Island, Norway (Lat: 66.42° N, Long: 13.13° E) and the other at 18.2 kHz from Vijayananarayanam, India (Lat: 8.4° N; Long: 77.7° E). The received signals exhibited their peak values on November 17, 2009 when ZHR (Zenithal Hourly Rate) was highest. Some typical variations which are observed in the records of amplitude during the 2009 Leonid, Perseid and Geminid meteor showers will be presented in this paper.  相似文献   

Studies on the Effects of 2009 Leonid Meteor Shower on Subionospheric Transmitted VLF Signals and Vertical Electric Potential Gradient     

S. S. De  B. Bandyopadhyay  S. Barui  Suman Paul  D. K. Haldar  D. De  B. K. De  S. Chattopadhyay  A. K. Kundu 《Earth, Moon, and Planets》2012,108(2):111-121

The effects of 2009 Leonid Meteor Shower upon the two VLF subionospheric transmitted signals and vertical electric potential gradient from the ground surface have been studied from Kolkata (Lat: 22.56°N, Long: 88.5°E) on November 17, 2009. The received signals showed their peak values when ZHR (Zenithal Hourly Rate) was highest. Some typical variations in the outcome of these measurements during the meteor showers will be presented in this paper.  相似文献   

Effect of Corrugation and Reinforcement on the Dispersion of SH-wave Propagation in Corrugated Poroelastic Layer Lying over a Fibre-reinforced Half-space   总被引：1，自引：1，他引：0  

Abhishek Kumar Singh  Amrita Das  Anirban Lakshman  Amares Chattopadhyay 《Acta Geophysica》2016,64(5):1340-1369

The presence of porosity and reinforcement in a medium is an important factor affecting seismic wave propagation and plays vital role in many geophysical prospects. Also, the presence of salt and ore deposits, mountains, basins, mountain roots, etc. is responsible for the existence of corrugated boundary surfaces of constituent layers. Such facts brought motivation for the present paper which deals with the propagation of SH-wave in a heterogeneous fluid-saturated poroelastic layer with corrugated boundaries lying over an initially stressed fibre-reinforced elastic halfspace. Closed form of dispersion relation has been obtained and is found in well agreement to classical Love wave equation for isotropic case. The effect of corrugation, wave number, undulation, position parameter, horizontal compressive/tensile initial stress and heterogeneity on phase velocity has been analysed through numerical computation and graphical illustration. Moreover, comparative study exploring the effect of presence and absence of reinforcement in half-space on dispersion curve is the major highlight of the current study.  相似文献   

Magnetoelastic shear waves in an infinite self-reinforced plate     

A. Chattopadhyay  S. Choudhury 《国际地质力学数值与分析法杂志》1995,19(4):289-304

The propagation of magnetoelastic shear waves in an infinite self-reinforced plate is studied in this paper. The frequency spectrum for SH-modes in the plate is drawn and it is shown that if the dimensionless wave number is real, the branches are hyperbolas while for imaginary wave numbers, they are ellipses. It is also observed that for higher modes, the dimensionless group velocity approaches 9·9754 as the wave number increases. The group velocity is normalized with respect to the phase velocity of shear waves. For a homogeneous and isotropic medium, on the other hand, the dimensionless group velocity approaches unity. So it is approximately 10 times larger in case of magnetoelastic shear waves in an infinite self-reinforced plate. It is also noted that in a reinforced medium, if both the values of the coupling parameter and the angle at which the wave crosses the primary magnetic field are increased, the values of the dimensionless frequency and group velocity are decreased.  相似文献   

Recent changes in the spatio-temporal characteristics of monsoon intraseasonal oscillations     

Joseph  Susmitha  Sahai  A. K.  Shabu  Hindhiya  Chattopadhyay  R.  Kaur  Manpreet 《Theoretical and Applied Climatology》2022,147(1-2):251-264

Theoretical and Applied Climatology - Monsoon intraseasonal oscillations (MISOs) define a significant proportion of intraseasonal variability of the Indian summer monsoon. In the backdrop of...  相似文献   

Application of criteria and indicators in community based sustainable mangrove management in the Sunderbans,India     

Debajit Datta  P. Guha  R.N. Chattopadhyay 《Ocean & Coastal Management》2010,53(8):468-477

Management of mangroves in a sustainable ecological as well as economic way is a difficult proposition and needs multi-disciplinary intervention. This paper highlights the importance of criteria and indicators to evaluate the status of performance of communities in managing their mangroves sustainably. The framework developed on the basis of 6 principles, 12 criteria, 36 indicators and 47 verifiers had been applied for assessment of Eco-Development Committees of the Sunderbans, India. Results show the presence of a highly positive correlation between performance of the committees and condition of the mangrove environment. Level of implementation of legal and institutional management strategies to protect mangroves proves to be the essential pre-condition in achieving sustainability. The study further demonstrates the effectiveness of the developed framework in the context of community forestry since the methodology was designed to be simple and flexible so as to apply it in forest management unit level without any major difficulty.  相似文献   

North Indian heavy rainfall event during June 2013: diagnostics and extended range prediction     

Susmitha Joseph  A. K. Sahai  S. Sharmila  S. Abhilash  N. Borah  R. Chattopadhyay  P. A. Pillai  M. Rajeevan  Arun Kumar 《Climate Dynamics》2015,44(7-8):2049-2065

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