In this paper, we consider the isoptic curves in 2-dimensional geometries of constant curvature E, H, E. The topic is widely investigated in the Euclidean plane E, see for example [1] and [15] and the references given there. In the hyperbolic and elliptic plane (according to [18]), there are few results in this topic (see [3] and [4]). In this paper, we give a review of the known results on iso...

This paper proves that an embedded compact surface in the Euclidean space with constant mean curvature H 6= 0 bounded by a circle of radius 1 and included in a slab of width 1=jHj is a spherical cap. Also, we give partial answers to the problem when a surface with constant mean curvature and planar boundary lies in one of the halfspaces determined by the plane containing the boundary, exactly, ...

Now a day centrifugal pumps are vital components of industries. Certainly, one of the most important specifications of centrifugal pumps are the performance curves. In the present work, performance curves of a centrifugal pumps are obtained by Computational fluid dynamics (CFD) and as an outcome, CFD results compare by practical curves. At the first step impeller and volute are designed with tw...

BACKGROUND AND PURPOSE Posterior fossa malformations are a common finding in prenatal diagnosis. The objectives of this study are to re-evaluate existing normal MR imaging biometric data of the fetal posterior fossa, suggest and evaluate new parameters, and demonstrate the possible clinical applications of these data. MATERIALS AND METHODS This was a retrospective review of 215 fetal MR imagi...

In this paper, we give a ‘direct’ construction of the endomorphism ring of supersingular elliptic curves over a prime field Fp from ‘ideal classes’ of Q( √−p). We use the result to prove that the result of Kaneko on ‘minimal’ CM liftings of such supersingular elliptic curves is a best possible result. We also prove that the result of Elkies on ‘minimal’ CM liftings of all supersingular elliptic...

As shown by Parker and Raval, quantum field theory in curved spacetime gives a possible mechanism for explaining the observed recent acceleration of the universe. This mechanism is consistent with a zero cosmological constant, and causes the universe to make a transition to an accelerating expansion in which the scalar curvature, R, of spacetime remains constant. We show that this model agrees ...

Lagrangian curves in R entertain intriguing relationships with second order deformation of plane curves under the special affine group and null curves in a 3-dimensional Lorentzian space form. We provide a natural affine symplectic frame for Lagrangian curves. It allows us to classify Lagrangrian curves with constant symplectic curvatures, to construct a class of Lagrangian tori in R and determ...

We consider robust variants of the bin packing problem with uncertain item sizes. Specifically we two uncertainty sets previously studied in literature. The first is budgeted (the $U^\Gamma$ model), which at most $\Gamma$ items deviate, each reaching its peak value, while other assume their nominal values. second set, $U^\Omega$ model, bounds total amount deviation scenario. show that a variant...