نتایج جستجو برای: gravitational flow

تعداد نتایج: 521737  

2000
J. X. Lu

In this short note, we try to clarify a seemly trivial but often confusing question in relating a higher-dimensional physical gravitational constant to its lower-dimensional correspondence in Kaluza-Klein reduction. In particular, we re-derive the low-energy M-theory gravitational constant in terms of type IIA string coupling gs and constant α ′ through the metric relation between the two theor...

2008
K. A. Bronnikov S. G. Rubin

We consider multidimensional gravity with a Lagrangian containing the Ricci tensor squared and the Kretschmann invariant. In a Kaluza-Klein approach with a single compact extra space of arbitrary dimension, with the aid of a slow-change approximation (as compared with the Planck scale), we build a class of spatially flat cosmological models in which both the observed scale factor a(τ) and the e...

1997
S. W. Allen

We present a detailed comparison of mass measurements for clusters of galaxies using ASCA and ROSAT X-ray data and constraints from strong and weak gravitational lensing. Our results, for a sample of thirteen clusters (including six with massive cooling flows, five without cooling flows, and two intermediate systems) provide a consistent description of the distribution of gravitating matter in ...

A.R Daneshkhah H.R Vosoughifar

In this research, the numerical method of computational fluid dynamics and dimensionless parameter of Froude number have been applied to determine the flow regime over ogee spillways.Froude number is a dimensionless dynamic parameter calculated using the square root of the ratio of inertia force and gravitational force. Considering that the study of the regimes of flow over hydraulic structures...

2002
John F. Hawley Steven A. Balbus

We analyze three-dimensional magnetohydrodynamic (MHD) simulations of a nonradiative accretion flow around a black hole using a pseudo-Newtonian potential. The flow originates from a torus initially centered at 100 gravitational (Schwarzschild) radii. Accretion is driven by turbulent stresses generated selfconsistently by the magnetorotational instability. The resulting flow has three well-defi...

Journal: :Micromachines 2014
Kaijun Yang

A novel hot embossing/low temperature ethanol solvent bonding method for the fabrication of polymethylmethacrylate (PMMA) field flow fractionation devices has been developed. The separation channel on a PMMA substrate was generated by a hot embossing process without vacuum. Special temperature-pressure profiles were used to analyze the influence of the hot embossing parameters. After the hot em...

2017
W. B. Houthoff A. Kurov F. Saueressig

We use a functional renormalization group equation tailored to the Arnowitt-Deser-Misner formulation of gravity to study the scale dependence of Newton's coupling and the cosmological constant on a background spacetime with topology [Formula: see text]. The resulting beta functions possess a non-trivial renormalization group fixed point, which may provide the high-energy completion of the theor...

2016
Eli Galanti Yohai Kaspi Eli Tziperman

The nature of the flow below the cloud level on Jupiter and Saturn is still unknown. Relating the flow on these planets to perturbations in their density field is key to the analysis of the gravity measurements expected from both the Juno (Jupiter) and Cassini (Saturn) spacecrafts during 2016–2018. Both missions will provide latitude-dependent gravity fields, which in principle could be inverte...

In this work, the gravitational collapse of a spherically symmetric null shell with the flat interior and a charged Vaidya exterior spacetimes is studied. There is no gravitational impulsive wave present on the null hypersurface which is shear-free and contracting. It follows that there is a critical radius at which the shell bounces and starts expanding.

2013
V. Raghavan George Gogos T. Sundararajan

Characteristics of methanol diffusion flames burning under three different configurations with respect to the directions of forced and natural convective flow fields are presented for zero and normal gravity conditions. Combustion of a spherical methanol particle and of a methanol film within a mixed convective environment, have been numerically simulated. The effects of gravity on aiding, oppo...

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