in the first part of this paper, some theorems are given for a riemannian manifold with semi-symmetric metric connection. in the second part of it, some special vector fields, for example, torse-forming vector fields, recurrent vector fields and concurrent vector fields are examined in this manifold. we obtain some properties of this manifold having the vectors mentioned above.

lead and zinc production is one of the main predisposing factors of excessive greenhouse gases emissions, air pollution and water consumption. in this paper, the environmental problems of lead and zinc production in calcimin plant are expressed and life cycle assessment of this plant is assessed. the data regarding the amount of induced global warming and pollution, acidification, and depletion...

The present investigation deals with the propagation of waves in a micropolar transversely isotropic layer. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitudes of displacements and microrotation were also obtained. Finally, the numerical solution was carried out for aluminium epoxy material and the dispersion curv...

today as freshwater resources become scarcer, wastewater use is a major incentive option for conserving and expanding available water supplies. the aim of this research was to investigate the impact of normal irrigation water (well water), chemical fertilizer, and treated urban wastewater effluent on yield quantity and quality of broccoli under micro irrigation system. the accumulation of chemi...

This paper presents a numerical method for studying water impact of a two-dimensional body of arbitrary cross-section. The global simulation procedure based on the boundary element method is constructed. The attention is focused on the computational description of the jet flow in the framework of a potential flow assumption. The proposed computational model makes the numerical analysis more sta...

The theory of electron impact ionization of oneand two-electron atoms has advanced significantly in the past two years. This paper will summarize the progress that the members of our research center have contributed to.

Abstrad In T U D envitnnnrm?b, o I)rOJ)cr vector disc:rc</izcr/ion i /wo or /hrw dimensiuns is N I I impurtunt isstre. Pllysiml models like tile impact ionization rate depend on vector quantities. Two discrerization mct11od.s fur Dc~Iuunuy rneslzes bused only on /17e zrtis/rrrc~urc~d ncig/?horhood ir?fomatioit are prc.vcnted. Ol~crall good conwGcmce is uc:hie~~e~I by upplying fhese me/liods in ...