in this paper, analysis of fluid flow and heat transfer over the bank of tubes is considered. k-ω sst model is applied for simulation of turbulent flow. in this paper, the improvement of efficiency of a bundle of circular tubes by changing the shape of the cross section of one row of the pipes to the elliptical cross section as an innovative plan is considered. as know, friction factor in turbu...

this study is conducted in universities located in ilam provinceto identify the factors affecting creative organization. the research methodis mixed, in that, statistic sample in qualitative section consists of expertsand in quantitative section consists of employees, professors, and top andmiddle managers in universities (payam-e-noor university, medicalsciences university, azad university and...

The resummation of threshold logarithms for direct photon production cross sections in hadronic collisions is presented. The resummation is based on the factorization properties of the cross section and is formulated at next-to-leading logarithmic or higher accuracy. Full analytical and numerical results for the next-to-next-toleading order expansion of the resummed cross section are given. A s...

background:the diagnostic accuracy of frozen section as an important source of information in surgical pathology is important not only in the management of surgical patients but also as a measure of quality control in surgical pathology. in this study, we evaluated the diagnostic accuracy of frozen sections over a 6-year period in a teaching hospital in iran. methods: we retrospectively review...

Focussing on preplanetary grains growth, we discuss the properties of dust aggregation driven by magnetic dipole forces. While there is no direct evidence for the existence of magnetic grains present in the solar nebula, there are reasons to assume they may have been present. We derive analytical expressions for the cross-section of two interacting dipoles. The effective cross section depends u...

Approximate approach for description of two-photon bremsstrahlung emitted by the relativistic projectile scattered in a spherically-symmetric filed of the target is suggested. It based on the accurate treatment of the analytical structure of singularities in relativistic one-photon free-free matrix elements. For the case of Coulomb field of the target the closed-form analytical expressions for ...

For the investigation of the S-wave boson-triboson phase shift, the Faddeev-Osborn equation is solved numerically by assuming a rank-one separable potential of the Yamaguchi type for the two-particle interaction. The calculation is performed in the exact approach based on rigorous Faddeev theory of the scattering problem. As a first step of the investigation, to gain insight into the origin of ...

The diffractive process γp → V + X (where V is a vector meson and X results from the dissociation of the proton) is studied. In particular, we consider the region of large momentum transfer (i.e. |t| ≫ ΛQCD) and large centre-of-mass (CM) energy, s. The asymptotic (s → ∞, s/|t| ≫ 1) behaviour is derived from the BFKL equation and compared to that which is obtained in the Born approximation (two-...