In this paper, we give a classification of non simply connected seven dimensional Reimannian manifolds of constant positive curvature which admit irreducible cohomogeneity-one actions. We characterize the acting groups and describe the orbits. The first and second homo-topy groups of the orbits have been presented as well.

in this paper, we give a classification of non simply connected seven dimensional reimannian manifolds of constant positive curvature which admit irreducible cohomogeneity-one actions. we characterize the acting groups and describe the orbits. the first and second homo-topy groups of the orbits have been presented as well.

A new guidance scheme for the problem of Low-thrust transfer between inclined orbits is developed within the framework of optimal control theory. The objective of the guidance scheme is to provide the appropriate thrust steering program that will transfer the vehicle from an inclined low earth orbits to the high earth orbits. The presented guidance scheme is determined using Pontryagin’s princi...

background and objectives: we aimed at evaluating the efficacy of fine needle aspiration biopsy (fna) in comparison with histopathology and demonstrating whether cytological study could be a proper diagnostic tool in orbital mass lesions. materials and methods: in a cross sectional study during 36 months, patients referred to our ophthalmologic center affiliated to tehran university of medical ...

A satellite, in its orbit, is affected by perturbing forces, such as atmospheric drag, solar radiation pressure, Earth oblateness, and gravity of the celestial masses (other than the Earth). In this paper, the effects of these forces on the trajectories of different types of LEO satellites and a sample satellite (Z-SAT) are discussed. A few analyses are done on these orbits and the relevant res...

the problem of relative motion control for spacecraft formation flying in eccentric orbits is considered in this paper. due to the presence of nonlinear dynamics and external disturbances, a robust fuzzy sliding mode controller is developed. the slopes of sliding surfaces of the conventional sliding mode controller are tuned according to error states using a fuzzy logic and reach the pre-define...