arXiv subjects

P. Woafo

Publications and source records attributed to P. Woafo.

4 recordsLinked to original sources

arXiv2019

Chaotic dynamics of piezoelectric mems based on maximal Lyapunov exponent and Smaller Alignment Index computations

We characterize the dynamical states of a piezoelectric microelectromechanical system (MEMS) using several numerical quantifers including the maximal Lyapunov exponent, the Poincare Surface of Section and a chaos detection method called the Smaller Alignment Index (SALI). The analysis makes use of the MEMS Hamiltonian. We start our study by considering the case of a conservative piezoelectric MEMS model and describe the behavior of some representative phase space orbits of the system. We show that the dynamics of the piezoelectric MEMS becomes considerably more complex as the natural frequency of the system's mechanical part decreases.This refers to the reduction of the stiffness of the piezoelectric transducer. Then, taking into account the effects of damping and time dependent forces on the piezoelectric MEMS, we derive the corresponding non-autonomous Hamiltonian and investigate its dynamical behavior. We find that the non-conservative system exhibits a rich dynamics, which is strongly influenced by the values of the parameters that govern the piezoelectric MEMS energy gain and loss. Our results provide further evidences of the ability of the SALI to efficiently characterize the chaoticity of dynamical systems.

physics.comp-ph↗

arXiv2017

Amplitude Stochastic Response of Rayleigh Beams to Randomly Moving Loads

We consider the problem of the nonlinear response of a Rayleigh beam to the passage of a train of forces moving with stochastic velocity. The Fourier transform and the theory of residues is used to estimate the mean-square amplitude of the beam, while the stochastic averaging method gives the stationary probability density function of the oscillations amplitude. The analysis shows that the effect of the load random velocities is highly nonlinear, leading to a nonmonotonic behavior of the mean amplitude versus the intensity of the stochastic term and of the load weight. The analytic approach is also checked with numerical simulations. The effect of loads number on the system response is numerically investigated.

physics.app-ph↗

arXiv2013

Quantum associative memory for the diagnosis of some tropical diseases

In this paper we present a model of Quantum Associative Memory which can be a helpful tool for physicians without experience or laboratory facilities, for the diagnosis of four tropical diseases (malaria, typhoid fever, yellow fever and dengue) which have similar symptoms. The memory can distinguish single infection from multi-infection. The algorithm used for Quantum Associative Memory is an improve model of original algorithm made by Ventura for Quantum Associative Memory. From the simulation results given, it appears that the efficiency of recognition is good when a particular symptom of a disease with a similar symptoms are inserted.

physics.med-ph↗

arXiv2013

Limiting effects of geometrical and optical nonlinearities on the squeezing in optomechanics

In recent experiments, the re-thermalization time of the mechanical resonator is stated as the limiting factor for quantum applications of optomechanical systems. To explain the origin of this limitation, an analytical nonlinear investigation supported by the recent successful experimental laser cooling parameters is carried out in this work. To this end, the effects of geometrical and the optical nonlinearities on the squeezing are studied and are in a good agreement with the experimental results. It appears that highly squeezed state are generated where these nonlinearities are minimized and that high nonlinearities are limiting factors to reach the quantum ground state.

quant-ph↗