نتایج جستجو برای: gravity

تعداد نتایج: 62883  

2012
T. Padmanabhan

In the study of horizon thermodynamics and emergent gravity two natural expressions for energy, E = 2T S (equipartition energy) and E = T S (Noether energy) arise which differ by a factor 2. I clarify the role of these two expressions in different contexts and show how E = T S is also closely related to the Noether charge arising from the boundary term of the Einstein–Hilbert action.

2002
Imed Limam Adil Abdalla

Trade among Arab countries has been very weak despite previous efforts to engage into different forms of regional economic integration. Using the flexible framework provided by the Gravity Model, the paper gives an order of magnitude of the main factors often presented in explaining the weakness of inter-Arab Trade. The results of the model together with several indicators about export profiles...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2015
arezou jafari ali shahmohammadi seyyed mohammad mousavi

in the present attempt, flow behavior and thermal convection of one type of nanofluids in a disc geometry was investigated using computational fluid dynamics (cfd). influence of gravity induced sedimentation also has been studied. the commercial software, fluent 6.2, has been employed to solve the governing equations. a user defined function was added to apply a uniform external magnetic field....

One of the most remarkable basis of the gravity data inversion is the recognition of sharp boundaries between an ore body and its host rocks during the interpretation step. Therefore, in this work, it is attempted to develop an inversion approach to determine a 3D density distribution that produces a given gravity anomaly. The subsurface model consists of a 3D rectangular prisms of known sizes ...

Gravity drainage is one of the important recovery mechanisms in fractured carbonate and conventional reservoirs. It occurs due to density difference between the gas in fracture and the oil in matrix as well as in conventional tilted reservoirs. Oil phase will form films which are produced under gravity forces (film flow). Many gas injection experiments have been done on laboratory scales with d...

2009
A. A. Kocharyan

We study nonrelativistic gravity using the Hamiltonian formalism. For the dynamics of general relativity (relativistic gravity) the formalism is well known and called the ADM formalism. We show that if the lapse function is constrained correctly, then nonrelativistic gravity is described by a consistent Hamiltonian system. Surprisingly, nonrelativistic gravity can have solutions identical to re...

The national height system of Iran, orthomertic height, is referred to geoid as the vertical datum. Consequently, the geoid has many important applications in engineering. The slow, laborious and expensive orthomertic heights can be obtained in sufficient accuracy level from geodetic height (derived by GNSS observations) and a precise geoidal height. Over the past two decades, the gravity divis...

ژورنال: ژئوفیزیک ایران 2019

Recently, interpretation of causative sources using components of the gravity gradient tensor (GGT) has had a rapid progress. Assuming N as the structural index, components of the gravity vector and gravity gradient tensor have a homogeneity degree of -N and - (N+1), respectively. In this paper, it is shown that the eigenvalues, the first and the second rotational invariants of the GGT (I1 and ...

ژورنال: ژئوفیزیک ایران 2017

Estimating the lateral depth variations of the Earth’s crust from gravity data is a non-linear ill-posed problem. The ill-posedness of the problem is due to the presence of noise in the data, and also the non-uniqueness of the problem. Particle Swarm Optimization (PSO) is a stochastic population-based optimizer, originally inspired by the social behavior of fish schools and bird flocks. PSO is ...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری استادیار، گروه فیزیک، دانشگاه حکیم سبزواری، سبزوار، ایران براتعلی فیض آبادی استادیار، گروه فیزیک، دانشگاه حکیم سبزواری، سبزوار، ایران وحید ابراهیم زاده اردستانی دانشیار، گروه فیزیک زمین، موسسه ﮊئوفیزیک دانشگاه تهران، ایران

the mapping of the crust-mantle boundary surface is an important geophysical task, which the method of seismic profiling has dealt with profitably. there are, however, areas where the crustal structure is not known up to the present, and where the moho has as yet not been determined by geophysical sounding. in such areas the isostatic theory may be applied to give a first estimate of the depths...

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