We seek to understand the behavior of a pendulum under parametric excitation coupled with nonlinear absorber. First, reference system without any absorber, i.e., simple pendulum, is analyzed multiple scale method thanks supposed assumptions about excitation. The equilibrium points are calculated, and their stability determined. phase portraits introduced in order better predict system. Then sam...

Accurate calculations of allowed and nonallowed transitions in porphyrin are reported. Using the quantum Monte Carlo method in the diffusion Monte Carlo variant, the vertical transition between the ground state singlet and the second excited state singlet as well as the adiabatic transition between the ground state and the lowest triplet state have been computed for this 162-electron system. Th...

Optical experiments on calf thymus DNA films subjected to different buffer environments are reported. The optical conductivity is that of a disordered or lightly doped semiconductor with a well-defined band-gap for charge excitations and low frequency transport determined by a small number of strongly localized electron states. The question whether electrons are delocalized along the DNA duplex...

A non-contact adhesion measurement technique based on acoustic base excitation and laser interferometery has been introduced and demonstrated. The vibrational motion of 21.4-microm polystyrene latex particles (PSL) microspheres on surfaces were excited in the frequency range of 0-3.5 MHz, and their axial displacement responses were measured by an interferometer. It is shown that the rolling mot...

High tall buildings are more susceptible to dynamic excitations such as wind and seismic excitations. In this paper, design procedure and some current applications of tuned mass damper (TMD) were studied. TMD was proposed to study response of 20 storey height building to seismic excitations using time history analysis with and without the TMD. The study indicates that the response of structur...

The paper presents an optimal fuzzy logic control algorithm for vibration mitigation of buildings using magneto-rheological (MR) dampers. MR dampers are semi-active devices and are monitored using external voltage supply. The voltage monitoring of MR damper is accomplished using evolutionary fuzzy system, where the fuzzy system is optimized using evolutionary algorithms (EAs). A micro-genetic a...

Structural control technology has been widely accepted as an effective means for the protection of structures against seismic hazards. Passive base isolation is one of the common structural control techniques used to enhance the performance of structures subjected to severe earthquake excitations. Isolation bearings employed at the base of a structure naturally increase its flexibility, but con...

To understand the mechanism of TATA-box conformational transformations we model structure mobility and find the types of conformational excitations of DNA macromolecule in heteronomous conformation. We have constructed the twocomponent model for describing DNA conformational transformation with simultaneous transitions in the furanos rings of the monomer link. Internal component describes the c...