the human brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. brain development begins in early gestation. between 4 weeks and 9 months, brain undergoes rapid development. there are six stages of nervous system development. brain increases connections between birth and 21 years of age. ab...

retrofitting structures is an important issue. structural weakness may be due to changes in design codes or defects in implementation. adding structural floors to the existing structures may also lead to the need for strengthening and retrofitting. retrofitting is possible before the earthquake or may take place as rehabilitation of damaged members after earthquake. elements such as columns in ...

eart pressure problems are encountered in retaining walls, bulkheads, sheeting and bracing in cuts,culverts, tunnels, and cofferdams. in many cases, the lateral pressure is determined by use of classical earth pressure theories, such as coulomb's, where the equilibrium conditions of a failure wedge of soil is considered. excessive dynamic lateral earth pressure on retaining structures resu...