منابع مشابه
Cylindrical wormholes
It is shown that the existence of static, cylindrically symmetric wormholes does not require violation of the weak or null energy conditions near the throat, and cylindrically symmetric wormhole geometries can appear with less exotic sources than wormholes whose throats have a spherical topology. Examples of exact wormhole solutions are given with scalar, spinor and electromagnetic fields as so...
متن کاملOnce again on thin-shell wormholes in scalar-tensor gravity
It has been recently proved in a general form [1] that no wormholes can be formed in any scalartensor theory (STT) of gravity in which the non-minimal coupling function f(Φ) is everywhere positive and the scalar field Φ itself is not a ghost if matter sources of gravity respect the Null Energy Condition (NEC). In order to construct any viable and stable wormhole solution, attempts have been rec...
متن کاملModelling of Random Geometrical Imperfections and Reliability Calculations for Thin Cylindrical Shell Subjected to Lateral Pressure
It is well known that it is very difficult to manufacture perfect thin cylindrical shell. Initial geometrical imperfections existing in the shell structure is one of the main determining factor for load bearing capacity of thin cylindrical shell under uniform lateral pressure. As these imperfections are random, the strength of same size cylindrical shell will also random and a statistical metho...
متن کاملFinite Element Analysis of Buckling of Thin Cylindrical Shell Subjected to Uniform External Pressure
One of the common failure modes of thin cylindrical shell subjected external pressure is buckling. The buckling pressure of these shell structures are dominantly affected by the geometrical imperfections present in the cylindrical shell which are very difficult to alleviate during manufacturing process. In this work, only three types of geometrical imperfection patterns are considered namely (a...
متن کاملLinearized stability analysis of thin-shell wormholes with a cosmological constant
Spherically symmetric thin-shell wormholes in the presence of a cosmological constant are constructed applying the cut-and-paste technique implemented by Visser. Using the Darmois-Israel formalism the surface stresses, which are concentrated at the wormhole throat, are determined. This construction allows one to apply a dynamical analysis to the throat, considering linearized radial perturbatio...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 2004
ISSN: 1550-7998,1550-2368
DOI: 10.1103/physrevd.70.044008