design and construction of efficient and economic reinforced concrete (r.c.) hyperbolic cooling towers have driven the engineers toward the design of tall and thin-shell towers which have considerable high slenderness aspect ratio. consequently, the shell of r.c. cooling towers with relative high slenderness aspect ratio is extremely prone to buckling instability due to wind loading. to increas...

This study aims to validate, using finite element analysis (FEA), the design concept by comparing the fatigue behavior of hip implant stems coated with composite (carbon/PEEK) and polymeric (PEEK) coating materials corresponding to different human activities: standing up, normal walking and climbing stairs under dynamic loadings to find out which of all these models have a better performance in...

  Background: Factor VII concentrates are used in patients with congenital or acquired factor VII deficiency or treatment of hemophilia patients with inhibitors. In this research, immunoaffinity chromatography was used to purify factor VII from prothrombin complex (Prothrombin-Proconvertin-Stuart Factor-Antihemophilic Factor B or PPSB) which contains coagulation factors II, VII, IX and X. The a...

failure of the quay walls due to earthquakes results in severe economic loss. because of hazards threatening such inexpensive nodes of national and international transportation networks, seismic design of quay walls is still an evolving topic in marine structural engineering. this study investigates the sensitivity of the gravity-type quay wall stability respect to uncertain soil and seismic pr...

In this paper we suggest a method to calculate the first integrals of a special system of the first order of differential equations. Then we use the method for finding the solutions of some differential equations such as, the differential equation of RLC circuit

in the current engineering practices, buildings are commonly designed for an effective lifetime of 50 years. this lifetime can increase the cost of buildings with short lifetimes and can reduce the safety level of buildings with large lifetimes. in this paper, a “service-life factor” has been defined. applying this factor into the nominal values of live, earthquake, wind, and snow loads, the ef...