concrete is one of the most widely used materials in construction industry. many large and important structures such as power plants, bridges, dams and buildings employ concrete as main material. propagation of crack is considered one of the main reasons in failure of concrete structures. the process of formation and crack growth is one of the major and complex issues in concrete, because concr...

the effect of weeds on yield of plants is variable during the plant growing periods. recognition of these critical periods is basically important for weed control. the gompertz and logistic are two mathematical models, which are suitable to study the presence of weed effect on the yield of plants. the main problem of using these models is calibration. in this study, a method is developed for mo...

Nowadays, due to high ratio of strength to weight, composite cylindrical shells are extensively used in a great variety of different industrial applications and under different cases of loads. In this study, the buckling of composite cylindrical shells was examined under uniform external pressure. The buckling analysis of composite cylindrical shells was first done by using theoretical relation...

in this paper‎, ‎we prove a multiplicity result for some biharmonic elliptic equation of kirchhoff type and involving nonlinearities with critical exponential growth at infinity‎. ‎using some variational arguments and exploiting the symmetries of the problem‎, ‎we establish a multiplicity result giving two nontrivial solutions‎.