نتایج جستجو برای: Gravity field

تعداد نتایج: 837945  

Journal: :iranian journal of science and technology (sciences) 2012
n. farhangkhah

the asymptotically ads solutions of the einstein gravity with hyperbolic horizons in the presence of so(n(n-1)/2- 1,1) yang-mills fields governed by the non-abelian born-infeld lagrangian are presented. we investigate the properties of these solutions as well as their asymptotic behavior in various dimensions. the properties of these kinds of solutions are like the einstein-yang-mills solutions...

R Kakar, S Kakar

The propagation of torsional waves in a prestressed fiber-reinforced half-space under the effect of magnetic field and gravity has been discussed. The problem has been solved analytically using Whittaker function to obtain the exact solution frequency equations. Numerical results for stress, gravity and magnetic field are given and illustrated graphically. Comparisons are made with the results ...

Journal: :فیزیک زمین و فضا 0
a safari department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran m.a sharifi department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran h amin department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran i foroughi department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran

gravity acceleration data have grand pursuit for marine applications. due to environmental effects, marine gravity observations always hold a high noise level. in this paper, we propose an approach to produce marine gravity data using satellite altimetry, high-resolution geopotential models and harmonic splines. on the one hand, harmonic spline functions have great capability for local gravity ...

ژورنال: فیزیک زمین و فضا 2014
A Safari H Amin I Foroughi M.A Sharifi

Gravity acceleration data have grand pursuit for marine applications. Due to environmental effects, marine gravity observations always hold a high noise level. In this paper, we propose an approach to produce marine gravity data using satellite altimetry, high-resolution geopotential models and harmonic splines. On the one hand, harmonic spline functions have great capability for local gravity ...

In this study, a numerical examination of the significance of rotation and changeable gravitational field on the start of nanofluid convective movement in an anisotropic porous medium layer is shown. A model that accounts for the impact of Brownian diffusion and thermophoresis is used for nanofluid, while Darcy’s law is taken for the porous medium. The porous layer is subjected to uniform rotat...

Journal: :فیزیک زمین و فضا 0
عبدالرضا صفری دانشیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران اسماعیل فروغی دانشجوی کارشناسی ارشد ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران هادی امین دانشجوی کارشناسی ارشد ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران

one of the most important problems in geodesy is the unification of height datum. generally in geodesy; there are two types of height systems, the geometrical height based on ellipsoid and the physical height based on gravity-defined surface (zhang et al, 2009).local height datum is determined according to mean sea level (msl). in regarding to mismatch of mean sea level and geoid, on the one ha...

حنیف محمدپور, , محمدحسین دهقانی, ,

 In this paper we consider the action of higher derivative gravity up to the second order terms in the scalars made from the Ricci scalar, Ricci and Riemann tensors. We use the Bach- Lanczos identity of the Weyl tensor in four dimensions and show that the solutions of 4-dimensional Einstein equations with cosmological constant term in vacuum, which are known as Einstein metrics, satisfy the fie...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری استادیار، دانشگاه تربیت معلم سبزوار وحید ابراهیم زاده اردستانی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران و قطب علمی مهندسی نقشه برداری و مقابله با سوانح طبیعی علیرضا آزموده اردلان استاد، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری در مقابله با سوانح طبیعی، پردیس دانشکده های فنی

measuring field gravity in sea due to the accelerations introduced via waves and movements to the gravity measuring systems has a low accuracy since according to einstein's equalent principle, gravimeter isn't able to separate the gravity acceleration from another acceleration. ship borne gravimetery observations by means of like oscillations and accelerations of the ship motion, and ...

Journal: :فیزیک زمین و فضا 0
مهروز خادمی کارشناس ارشد ژئودزی، گروه مهندسی نقشه برداری، دانشکده نقشه برداری، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران مهدی نجفی علمداری دانشیار، گروه مهندسی نقشه برداری، دانشکده نقشه برداری، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران

the recent dedicated satellite gravimetry missions have provided huge amount of high quality gravity data with global coverage. from computational point of view, estimation of the unknown gravity field parameters is a highly demanding task due to the sheer number of observations and the unknown coefficients. different computational schemes have been proposed to tackle the problem. since the ear...

Journal: :Results in Physics 2013

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