Designing a New Type of Energy Trap: A Classical Analog of Quantum Landau-Zener Tunneling

2011 ◽  
Author(s):  
Alexander F. Vakakis ◽  
Grigori Sigalov ◽  
Mercedes Mane ◽  
Lawrence A. Bergman ◽  
Leonid I. Manevitch ◽  
...  
Keyword(s):  
Mechanical Systems ◽  
Energy Trap ◽  
Oscillatory Systems ◽  
Weakly Coupled ◽  
Coupled Subsystems ◽  
Asymptotic Equations ◽  
Theoretical Predictions ◽  
New Type ◽  
Zener Tunneling ◽  
Pass Through

We present a novel type of energy trap providing targeted energy transfer (TET) in a system of weakly coupled pendulums. Our approach is based on the analogy, presented in [1, 2], between the behavior of two weakly coupled classical parametric pendulums and nonadiabatic Landau-Zener tunneling (LZT) in a two-state quantum system. The two systems, however dissimilar, turn out to be described by the same asymptotic equations. Well-known properties of LZT allow us to predict the possibility of efficient irreversible transfer of vibration energy from one subsystem to another in mechanical systems. The TET takes place when the eigenfrequency of a subsystem changes in time so that the coupled subsystems pass through internal resonance. The existence of such a phenomenon is not restricted to coupled pendulums but is inherent to a wide class of both linear and nonlinear parametric oscillatory systems. This opens up the possibility of designing new types of energy traps and absorbers for the dynamic protection of various mechanical systems. Experimental data obtained in this work corroborate theoretical predictions.

Towards a new type of energy trap: Classical analog of quantum Landau-Zener tunneling

2011 ◽  
Vol 46 (1) ◽  
pp. 247-252 ◽  
Author(s):  
Leonid I. Manevitch ◽  
Yury A. Kosevich ◽  
Mercedes Mane ◽  
Grigori Sigalov ◽  
Lawrence A. Bergman ◽  
...  
Keyword(s):  
Classical Analog ◽  
Energy Trap ◽  
New Type ◽  
Zener Tunneling

New devices for unidirectional acoustic cloaking for large objects in infinite frequency bandwidth

2018 ◽  
Vol 32 (24) ◽  
pp. 1850264
Author(s):  
Xiaopeng Wang ◽  
Yu Han ◽  
Lele Wan ◽  
Tianning Chen ◽  
Ailing Song
Keyword(s):  
Plane Waves ◽  
Propagation Direction ◽  
Infinite Length ◽  
Frequency Bandwidth ◽  
Frequency Range ◽  
Incident Plane ◽  
Theoretical Predictions ◽  
New Type ◽  
Pass Through ◽  
Invisibility Cloaks

For years, researchers struggled to realize the acoustic invisibility cloaks with simple for large objects in broadband. In this paper, a new-type unidirectional acoustic cloak is proposed and designed by using eight especial triangles region filled with a certain refractive index inert gas. The acoustic wave can be manipulated to pass through the model but “by-pass” the cloaked region according to the traditional Snell’s law. The incident plane waves will remain without any change. Therefore, the cloaked region cannot be detected. Our designed cloak can realize the infinite length of the invisibility region along the propagation direction and offer good cloaking effect in any frequency range. The simulation results agree well with the theoretical predictions and verify the nondetectability effect of the unidirectional acoustic cloak. Our mechanism may be useful for further actual applications in hiding large objects acoustically.

Prelude: A Sense of Place

2016 ◽  
Author(s):  
Connor J. Fitzmaurice ◽  
Brian J. Gareau
Keyword(s):  
Social Relations ◽  
Sense Of Place ◽  
Food System ◽  
Social Connection ◽  
Commodity Chains ◽  
Farming Practice ◽  
Organic Products ◽  
New Type ◽  
Pass Through

The conventionalization of the organic sector has led many to be skeptical about the possibility of organic in and of itself promoting a meaningfully sustainable alternative to the modern agricultural paradigm. However, the bifurcation of the organic market into both mainstream and alternative spheres provides places within the food system where investigating the work involved in creating new economic and social relations of farming practice makes sense. We may very well have come to an era in which most organic products pass through the same types of industrial commodity chains as organic initially set out to challenge. But more and more people desire a new type of economy, one that fosters social connection, meaning, and new relationships of exchange (...

Flexural Wave Propagation of Double-Layered Graphene Sheets Based on the Hamiltonian System

2020 ◽  
Vol 975 ◽  
pp. 121-126
Author(s):  
Cheng Hui Xu ◽  
Jing Jing Hu ◽  
Da Lun Rong
Keyword(s):  
Wave Propagation ◽  
Plate Theory ◽  
Mechanical Systems ◽  
Chemical Properties ◽  
Nonlocal Elasticity Theory ◽  
Flexural Wave ◽  
Graphene Sheets ◽  
Hamiltonian Equation ◽  
New Type ◽  
Flexural Wave Propagation

Double-layered graphene sheets (DLGSs) as a new type of nanocomponents, with special mechanical, electrical and chemical properties, have the potential of being applied in the nanoelectro-mechanical systems (NEMS) and nanoopto-mechanical systems (NOMS). In DLGSs structure, the two graphene sheets are connected by van der Waals (vdW) interaction. Thus, it can exhibit two vibration modes during the propagation of the flexural wave, i.e., in-phase mode and anti-phase mode. Based on the Kirchhoff plate theory and the nonlocal elasticity theory, Hamiltonian equations of the DLGSs are established by introducing the symplectic dual variables. By solving the Hamiltonian equation, the dispersion relation of the flexural wave propagation of the DLGSs is obtained. The numerical calculation indicates that the bending frequency, phase velocity and group velocity of the in-phase mode and anti-phase mode for the DLGSs are closely related to the nonlocal parameters, the foundation moduli and the vdW forces. The research results will provide theoretical basis for the dynamic design of DLGSs in micro-nanofunctional devices.

Coupled Oscillatory Systems with 𝔻4 Symmetry and Application to van der Pol Oscillators

2016 ◽  
Vol 26 (08) ◽  
pp. 1650141 ◽  
Author(s):  
Adrian C. Murza ◽  
Pei Yu
Keyword(s):  
Hopf Bifurcation ◽  
Periodic Solutions ◽  
Coupled Oscillators ◽  
Invariant Manifolds ◽  
Van Der Pol ◽  
Normal Form Theory ◽  
Oscillatory Systems ◽  
Weakly Coupled ◽  
Form Theory ◽  
Van Der Pol Oscillators

In this paper, we study the dynamics of autonomous ODE systems with [Formula: see text] symmetry. First, we consider eight weakly-coupled oscillators and establish the condition for the existence of stable heteroclinic cycles in most generic [Formula: see text]-equivariant systems. Then, we analyze the action of [Formula: see text] on [Formula: see text] and study the pattern of periodic solutions arising from Hopf bifurcation. We identify the type of periodic solutions associated with the pairs [Formula: see text] of spatiotemporal or spatial symmetries, and prove their existence by using the [Formula: see text] Theorem due to Hopf bifurcation and the [Formula: see text] symmetry. In particular, we give a rigorous proof for the existence of a fourth branch of periodic solutions in [Formula: see text]-equivariant systems. Further, we apply our theory to study a concrete case: two coupled van der Pol oscillators with [Formula: see text] symmetry. We use normal form theory to analyze the periodic solutions arising from Hopf bifurcation. Among the families of the periodic solutions, we pay particular attention to the phase-locked oscillations, each of them being embedded in one of the invariant manifolds, and identify the in-phase, completely synchronized motions. We derive their explicit expressions and analyze their stability in terms of the parameters.

scholarly journals THEORETICAL MODEL AND DESIGN OF A NOVEL STATIC POLARIZATION WIND IMAGING INTERFEROMETER (NSPWII)

2020 ◽  
Vol V-1-2020 ◽  
pp. 383-388
Author(s):  
C. Zhang ◽  
T. Yan ◽  
T. Mu ◽  
Y. He
Keyword(s):  
Theoretical Model ◽  
Wind Field ◽  
Michelson Interferometer ◽  
Atmospheric Temperature ◽  
Imaging Interferometer ◽  
New Type ◽  
Field Velocity ◽  
Static Polarization ◽  
Pass Through ◽  
Light Beams

Abstract. Polarization array based polarization Michelson wind field detection interferometer is a new type of interferometer for detecting atmospheric temperature and wind field velocity. We proposed a theoretical model and design of the novel static polarization wind imaging interferometer (NSPWII). It consists of a group of polarizers and waveplates, a polarization beamsplitter, a field widened Michelson interferometer, a pyramid prism, and a polarization array. Based on the principle of polarization interference, a polarization array composed of four polarizers with 45° polarization directions differences is directly in front of the detector, and four modulated light beams from the pyramid prism pass through the four polarizers. Then, interferograms with four different intensity are imaged on the detector simultaneously, which further provides the atmospheric temperature and wind field velocity. The advantages of this instrument are static (no moving parts), achromatic, and temperature compensated. It is capable of measuring the upper atmospheric wind field in real time with a high precision.

scholarly journals Independent Markov decomposition: Toward modeling kinetics of biomolecular complexes

2021 ◽  
Vol 118 (31) ◽  
pp. e2105230118
Author(s):  
Tim Hempel ◽  
Mauricio J. del Razo ◽  
Christopher T. Lee ◽  
Bryn C. Taylor ◽  
Rommie E. Amaro ◽  
...  
Keyword(s):  
Cell Biology ◽  
Molecular System ◽  
Md Simulations ◽  
Weakly Coupled ◽  
Coupled Subsystems ◽  
Biomolecular Complexes ◽  
System States ◽  
State Models ◽  
Long Timescales ◽  
Kinetics Of

To advance the mission of in silico cell biology, modeling the interactions of large and complex biological systems becomes increasingly relevant. The combination of molecular dynamics (MD) simulations and Markov state models (MSMs) has enabled the construction of simplified models of molecular kinetics on long timescales. Despite its success, this approach is inherently limited by the size of the molecular system. With increasing size of macromolecular complexes, the number of independent or weakly coupled subsystems increases, and the number of global system states increases exponentially, making the sampling of all distinct global states unfeasible. In this work, we present a technique called independent Markov decomposition (IMD) that leverages weak coupling between subsystems to compute a global kinetic model without requiring the sampling of all combinatorial states of subsystems. We give a theoretical basis for IMD and propose an approach for finding and validating such a decomposition. Using empirical few-state MSMs of ion channel models that are well established in electrophysiology, we demonstrate that IMD models can reproduce experimental conductance measurements with a major reduction in sampling compared with a standard MSM approach. We further show how to find the optimal partition of all-atom protein simulations into weakly coupled subunits.

scholarly journals Dynamic absorber for ropeway gondola using Coriolis force

2008 ◽  
Vol 30 (4) ◽  
Author(s):  
Hiroshi Matsuhisa ◽  
Masashi Yasuda
Keyword(s):  
Natural Frequency ◽  
Coriolis Force ◽  
Large Amplitude ◽  
Theoretical Predictions ◽  
New Type ◽  
Small Model ◽  
Dynamic Absorber

Wind-induced swinging of ropeway gondola can be reduced using dynamic absorbers. To maximize the performance of conventional dynamic absorbers, their location should be as high as possible. However, absorbers can not be installed at high positions due to interference issues with structures such as towers and stations. To address this problem, a new type of dynamic absorber that moves vertically is proposed. This absorber is composed of a mass supported by a spring. The mass moves in the radius direction (up and down) and it induces Coriolis force in the circumference direction to prevent the swing of gondola. If the natural frequency of the absorber is tuned to twice that of the gondola, the absorber moves spontaneously with a large amplitude due the resonance. This absorber is more effective when it is located at lower positions. The experiment with a small model and an actual gondola for 10 passengers were carried out and the results agreed well with the theoretical predictions.

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