We study the flow-coupled vibrations of an unbalanced rotor and a floating sealing ring. The rotor is high speed1 its operating regimes are above second critical velocity. The ring is subjected to Coulomb friction force, which prevents its motion about the casing. At rotor rotation, the intensive vibrations of rotor and floating ring take place and the hydrodynamic forces in clearance between them are dominated. Non-impact and impact regimes are revealed and the latter are very dangerous for safety. In the stationary case, the analytical solutions for impact regimes are obtained1 these show that synchronous oscillations of rotor and floating ring may occur. The non-stationary oscillations during startup and shutdown are also considered. Domains for the trouble-free non-impact regimes by various rotor velocities are determined. Rotor trajectories with impacts are submitted.

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The chapter will present the classification of the types of modern terrorism and describe scenarios and probabilistic models of ordinary, technological, and the so-called intelligent terrorism that are distinguished by their triggering events, propagation modes, damaging factors, probabilities, and consequences. A comparative assessment of these three types of terrorism is presented. Dynamic three-sided models allow assessing the situation from standpoints of terrorists and law enforcement agencies, the administration of the complex engineering system, and analyzing actions and counteractions of various sides involved. A new comprehensive approach to ensuring complex engineering system security is described. This approach is focused not only on the development of protection barriers and safeguards against predetermined list of design-basis scenarios of terrorist attacks but also on increasing the system's resilience toward beyond design-basis attack scenarios.