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Internal Vibration and Synchronization of Four Coupled Self-Excited Elastic Beams  [PDF]
Miguel A. Barron
Open Journal of Applied Sciences (OJAppS) , 2016, DOI: 10.4236/ojapps.2016.68050
Abstract: The vibration behavior and the synchronization between some internal points of four coupled self-excited beams are numerically studied. Coupling through the root of the beams is considered. The transverse displacements of the internal points and the beam tips are monitored, and the power spectra of the resulting time series are employed to determine the oscillation frequencies. The synchronization between beams is analyzed using phase portraits and correlation coefficients. Numerical results show multiple frequencies in the vibration pattern, and complex patterns of synchronization between pairs of beams.
Photoacoustic elastic oscillation and characterization  [PDF]
Fei Gao,Xiaohua Feng,Yuanjin Zheng
Physics , 2014, DOI: 10.1364/OE.23.020617
Abstract: Photoacoustic imaging and sensing have been studied extensively to probe the optical absorption of biological tissue in multiple scales ranging from large organs to small molecules. However, its elastic oscillation characterization is rarely studied and has been an untapped area to be explored. In literature, photoacoustic signal induced by pulsed laser is commonly modelled as a bipolar "N-shape" pulse from an optical absorber. In this paper, the photoacoustic damped oscillation is predicted and modelled by an equivalent mass-spring system by treating the optical absorber as an elastic oscillator. The photoacoustic simulation incorporating the proposed oscillation model shows better agreement with the measured signal from an elastic phantom, than conventional photoacoustic simulation model. More interestingly, the photoacoustic damping oscillation effect could potentially be a useful characterization approach to evaluate biological tissue's mechanical properties in terms of relaxation time, peak number and ratio beyond optical absorption only, which is experimentally demonstrated in this paper.
Elastic scattering of electron vortex beams in magnetic matter  [PDF]
Alexander Edstr?m,Axel Lubk,Ján Rusz
Physics , 2015,
Abstract: We present a model to describe the elastic scattering of electrons in magnetic matter and, based on this model, we propose a new method for measuring magnetic properties of matter utilizing electron vortex beams. The method relies on interaction of the orbital angular momentum of the electron beam with the magnetic field in the sample in the elastic scattering regime. Complementary to Lorentz microscopy, this method is sensitive to out-of-plane magnetization. Considering the latest developments in generation of electron vortex beams, the method can achieve spatial resolution down to single atomic columns.
Numerical analysis of beams on unilateral elastic foundation  [PDF]
W. Torbacki
Archives of Materials Science and Engineering , 2008,
Abstract: Purpose: The main issue of this paper is to present results of finite element analysis of beams elements onunilateral elastic foundation received with a use of special finite elements of zero thickness designated forfoundation modelling.Design/methodology/approach: Computer strength analysis with a use of Finite Element Method (FEM)was carried out.Findings: The paper presents possibilities of special finite elements of zero thickness which enable takinginto consideration unilateral contact in construction-foundation interaction as well as an impact of surroundingconstruction environment to its behaviour.Research limitations/implications: Further researches should concentrate on taking into consideration amulti-layer aspects as well as elasto-plasticity of foundation.Practical implications: Modern engineering construction on elastic foundation analyze require not onlystandard analysis on Winkler (one parameter) foundation but also calculation of construction on two-parameterfoundation which will take into consideration a possibility of loosing contact between construction and foundation(unilateral contact).Originality/value: The paper can be useful for person who performs strength analysis of beams on elasticfoundation with a use of finite element method.
Time delay control of symmetry-breaking primary and secondary oscillation death  [PDF]
A. Zakharova,I. Schneider,Y. N. Kyrychko,K. B. Blyuss,A. Koseska,B. Fiedler,E. Sch?ll
Physics , 2013, DOI: 10.1209/0295-5075/104/50004
Abstract: We show that oscillation death as a specific type of oscillation suppression, which implies symmetry breaking, can be controlled by introducing time-delayed coupling. In particular, we demonstrate that time delay influences the stability of an inhomogeneous steady state, providing the opportunity to modulate the threshold for oscillation death. Additionally, we find a novel type of oscillation death representing a secondary bifurcation of an inhomogeneous steady state.
Polarized gamma beams on the base of excited crystal  [PDF]
A. Aganyants
Physics , 2003,
Abstract: Possibilities of creating high energy polarized photon beams at the end of bremsstrahlung spectrum and a method for analysis of degree of the beam polarization are considered in this paper.
Oscillation death in diffusively coupled oscillators by local repulsive link  [PDF]
C. R. Hens,Olasunkanmi I. Olusola,Pinaki Pal,Syamal K. Dana
Physics , 2013, DOI: 10.1103/PhysRevE.88.034902
Abstract: A death of oscillation is reported in a network of coupled synchronized oscillators in presence of additional repulsive coupling. The repulsive link evolves as an averaging effect of mutual interaction between two neighboring oscillators due to a local fault and the number of repulsive links grows in time when the death scenario emerges. Analytical condition for oscillation death is derived for two coupled Landau-Stuart systems. Numerical results also confirm oscillation death in chaotic systems such as a Sprott system and the R\"ossler oscillator. We explore the effect in large networks of globally coupled oscillators and find that the number of repulsive links is always fewer than the size of the network.
Oscillation Measurements with Upgraded Conventional Neutrino Beams  [PDF]
V. Barger
Physics , 2001,
Abstract: We consider the nu_mu to nu_e oscillation measurements that would be possible at upgraded 1 GeV and multi-GeV conventional neutrino sources driven by future megawatt-scale proton drivers. If these neutrino superbeams are used together with detectors that are an order of magnitude larger than those presently foreseen, we find that the sensitivity to nu_mu to nu_e oscillations can be improved by an order of magnitude beyond the next generation of accelerator based experiments. In addition, over a limited region of parameter space, the neutrino mass hierarchy can be determined with a multi-GeV long baseline beam. If the Large Mixing Angle MSW solution correctly describes the solar neutrino deficit, there is a small corner of allowed parameter space in which maximal CP-violation in the lepton sector might be observable at a 1 GeV medium baseline experiment. Superbeams with massive detectors would therefore provide a useful tool en route to a neutrino factory, which would permit a further order of magnitude improvement in sensitivity, together with a more comprehensive check of CP-violation and the oscillation framework.
On the Non-Linear Deformation of Elastic Beams in an Analytic Solution  [PDF]
N. Tolou,J. Mahmoudi,M. Ghasemi,I. Khatami
Asian Journal of Scientific Research , 2008,
Abstract: Non-linear dynamic of Elastic beams is investigated analytically. Homotopy Perturbation Method (HPM) is used to obtain the analytical solution of the fourth-order non-linear governing equation of beams. To demonstrate the validity of the proposed methods, the results which is obtained from the approximate solution has been shown graphically and compared with that obtained from the numerical solution. A clear conclusion can be drawn from the numerical results that the HPM provides highly accurate solutions for such nonlinear phenomenon.
Phase Space Distribution Near Self-Excited Oscillation Threshold  [PDF]
Yuvaraj Dhayalan,Ilya Baskin,Keren Shlomi,Eyal Buks
Physics , 2013, DOI: 10.1103/PhysRevLett.112.210403
Abstract: We study phase space distribution of an optomechanical cavity near the threshold of self-excited oscillation. A fully on-fiber optomechanical cavity is fabricated by patterning a suspended metallic mirror on the tip of the fiber. Optically induced self-excited oscillation of the suspended mirror is observed above a threshold value of the injected laser power. A theoretical analysis based on Fokker-Planck equation evaluates the expected phase space distribution near threshold. A tomography technique is employed for extracting phase space distribution from the measured reflected optical power vs. time in steady state. Comparison between theory and experimental results allows the extraction of device's parameters.
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