March 2013

Methodological approach of selecting a vibration indicator in monitoring bearings

A rolling bearing is an important element in a rotating machine. Whatever the operating conditions, it is subject to fatigue which causes spalling. In aiming to obtain the most possible real fatigue curve, the vibration level is shown according to different statistical indicators such as the RMS (Root Mean Square), the kurtosis, the crest value, the crest factor and the peak ratio, then to choose the best of them that...

Author(s): O. Djebili, F. Bolaers, A. Laggoun and J. P. Dron

March 2013

Effective rigid perfectly plastic models to predict deflection and residual velocity of post local failure motion of impulsively loaded circular plates

Two deformation models are proposed for clamped circular plates undergoing pulse loadings. By these models, behaviors of plate are studied effectively for the situations before and after local failure. In the first model, it is assumed that impulsive load is uniformly distributed and final deformation is of a spherical dome shape. In order to analyze this model, it assumed that under the shock wave, the mechanism of...

Author(s): Asghar Zajkani, Morteza Nikooyiha, Abolfazl Darvizeh and Mansour Darvizeh

March 2013

Studies on energy absorption and exposure buildup factors in some solutions of alkali metal chlorides

Buildup of photons has been investigated through the solutions LiCl, NaCl and KCl with different salt contents in the energy region 0.015-15 MeV up to a penetration depth of 40 mean free paths. Two types of buildup factors, the gamma ray energy absorption () and exposure buildup factors () have been calculated simultaneously using the five parameter geometric progression (G-P) fitting formula. The influence of photon...

Author(s): D. Sardari and M. Kurudirek

March 2013

Correction of topological errors in geospatial databases

The problems related to geometrical correctness of maps gathered and stored by the geographic information system (GIS) computer systems are still present nowadays. Firstly, digitization of traditional paper maps is still in progress all over the world (the maps are being converted to a vector form and stored in relational databases). Secondly, the existing digital maps are being constantly updated with use of manual and...

Author(s): Siejka M., Åšlusarski M. and Zygmunt M.