Unsteady hydromagnetic boundary-layer flow on a semi-infinite wall     

G. C. Pande  P. Hatzikonstantinou 《Astrophysics and Space Science》1985,113(2):281-288

Unsteady two-dimensional flow of a viscous, incompressible and electrically conducting fluid which is confined on one side of a semi-infinite wall, in presence of a transverse magnetic field is investigated. The wall is initially at rest and then it is suddenly accelerated in its own plane with a velocity which is an arbitrary function of the time. Solution of the problem is obtained, for two particular cases, i.e., corresponding to two free-stream velocities, with the help of the finite difference approximation technique using the explicit method for uniformly accelerated motion of the wall.  相似文献   

Gravitational collapse of a dust ball — The external observer's point of view     

M. C. Durgapal  A. K. Pande 《Astrophysics and Space Science》1985,116(2):349-354

The problem of collapse of a dust ball has been studied in detail from the point of view of an external observer (O). It is seen that although there is no material pressure from the point of view of the comoving observer, there is a non-vanishing material pressure in the ball from the point of view of O. In the early stages of collapse (w.r.t. O), this pressure is positive everywhere inside the ball, while during the later stages, if one goes outwards from the centre towards the surface of the ball, this pressure is negative up to a certain value of the radial coordinate, and then changes its sign thereafter. On the basis of this pressure, one can understand the physics of the whole scenario of collapse w.r.t. O; in particular, the important feature is that in the ultimate stages an event horizon is formed asymptotically and there is no collapse to a point (as takes place from the point of view of the comoving observer).  相似文献   

A possible presence of HeH+ in white dwarfs     

V. P. Gaur  G. C. Joshi  M. C. Pande 《Astrophysics and Space Science》1992,197(1):57-60

The equivalent width calculations for the fundamental vibration rotation band lines of HeH⁺ have been carried out for a non-DA white dwarf model with an effective temperature of 12 000 K. BothP andR branch lines with rotational quantum numbersJ=3 to 18 were included in the calculations. A search for these lines in helium rich white dwarfs is suggested.  相似文献   

Extreme relativistic model for neutron stars and pulsars     

M. C. Durgapal  A. K. Pande  P. S. Rawat 《Astrophysics and Space Science》1983,90(1):117-126

Exact solutions have been obtained for a massive fluid sphere under the extreme causality condition (dP/dρ)=1. Radial pulsational stability of these structures has been discussed. It is found that for pulsationally stable configurations the surface to central density ratio is greater than 0.30, the maximum values for surface and central redshifts are 0.85 and 3.40 respectively in the extreme case, and the maximum mass and size are respectively 4.8M _⊙ and 20.1 km. It has also been shown that these structures are gravitationally bound, with a maximum binding energy per unit rest mass equal to 0.25 for a surface to central density ratio ?0.40. Slow rotation of these configurations has also been considered, and the relative drag and moment of inertia have been calculated. These results have been applied to the Crab pulsar and the mass of the pulsar has also been calculated based upon this model.  相似文献   

Use of laser range and height texture cues for building identification   总被引：1，自引：0，他引：1  

Poonam S. Tiwari  Hina Pande 《Journal of the Indian Society of Remote Sensing》2008,36(3):227-234

Airborne LiDAR has found application in an increasing number of mapping and Geo-data acquisition tasks. Apart from terrain information generation, applications such as automatic detection and modeling of objects like buildings or vegetation for the generation of 3-D city models have been explored. Besides the height itself, height texture defined by local variations of the height is a significant parameter for object recognition. The paper explores the potential of the analysis of height texture as a cue for the automatic detection of objects in LiDAR datasets. A number of texture measures were computed. Based on their definition and computation these measures were used as bands in a classification algorithm, and objects like buildings, single trees, and roads could be recognized.  相似文献   

Hydromagnetic Rayleigh problem for a porous wall in slip flow regime     

G. C. Pande  C. L. Goudas 《Astrophysics and Space Science》1996,243(2):285-289

An analysis of the Rayleigh problem in MHD for a porous wall in a slip flow regime is considered. The normal velocity of suction/injection at the wall is assumed to be time dependent. The solution of the problem is obtained in the form of a power series, in terms of known functions. The variations of the velocity field and the skin friction are shown graphically and are followed by a quantitative discussion.Science Update, The Pioneer, India, 21 July 1995 edition  相似文献   

Massive configurations with constant densities     

M. C. Durgapal  A. K. Pande  K. Pandey 《Astrophysics and Space Science》1982,88(2):469-475

Two new classes of solutions with constant observed proper and rest mass densities are described. Unlike the well-known solution of constant coordinate mass density, these solutions pertain to realistic physical situations. For these solutions, the various relevant parameters, viz. the redshifts (dP/d)₀ and binding coefficients have been calculated.  相似文献   

40Ar/39Ar geochronology and geochemistry of the Central Saurashtra mafic dyke swarm: insights into magmatic evolution,magma transport,and dyke-flow relationships in the northwestern Deccan Traps     

Ciro Cucciniello  Elena I. Demonterova  Hetu Sheth  Kanchan Pande  Anjali Vijayan 《Bulletin of Volcanology》2015,77(5):1-19

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40Ar/39Ar geochronology of subaerial lava flows of Barren Island volcano and the deep crust beneath the Andaman Island Arc,Burma Microplate     

Jyotiranjan S. Ray  Kanchan Pande  Rajneesh Bhutani 《Bulletin of Volcanology》2015,77(6):1-10

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An overview of the opportunities and challenges of promoting climate change adaptation at the local level: a case study from a community adaptation planning in Nepal     

Bimal Raj Regmi  Cassandra Star  Walter Leal Filho 《Climatic change》2016,138(3-4):537-550

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