Rearrangement of lattice particles.
The internal rate of return (IRR) together with the present value (PV) is used as a popular measure for financial project. When used appropriately, it can be a valuable aid in project acceptance or selection. The purpose of this article is to survey the facts about this criterion published so far. More, we investigate the cases of multiple or nonexistent IRRs and try to choose the relevant one and explain its economic meaning.
The pendulum damper modelled as a two degree of freedom strongly non-linear auto-parametric system is investigated using two approximate differential systems. Uni-directional harmonic external excitation at the suspension point is considered. Semi-trivial solutions and their stability are analyzed. The thorough analysis of the non-linear system using less simplification than it is used in the paper [2] is performed. Both approaches are compared and conclusions are drawn.