IMPLEMENTATION OF INTERNAL-RESONANCE LASER SPECROSCOPY IN THE EXAMINATION OF THE ELECTROPHYSICAL CHARACTERISTICS OF BLOOD ELEMENTS

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

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Internal resonance characteristics of hyperelastic thin-walled cylindrical shells composed of Mooney–Rivlin materials

Thin-Walled Structures ◽

10.1016/j.tws.2021.107754 ◽

2021 ◽

Vol 163 ◽

pp. 107754

Author(s):

Wei Zhao ◽

Jing Zhang ◽

Wenzheng Zhang ◽

Xuegang Yuan

Keyword(s):

Internal Resonance ◽

Cylindrical Shells ◽

Thin Walled

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Formation and Destruction of Platelet Aggregates in Viscometric Flow

10.1055/s-0039-1689398 ◽

1975 ◽

Author(s):

H. Rieger ◽

H. Schmid-Schönbein

Keyword(s):

Initial Rate ◽

Aggregate Stability ◽

Creeping Flow ◽

Experimental Conditions ◽

Shear Rates ◽

Independent Variables ◽

Lower Shear ◽

Platelet Aggregates ◽

Blood Elements ◽

Shape Changes

Even after pseudopodia formation platelets - unlike all other known formed blood elements - remain dispersed in stasis and creeping flow and become aggregated only in the presence of a minimum amount of shearing. The “rheoaggregometer” (Rieger et al., Pflüger’s Archiv, 343, R 33, 1973) allows to measure the minimum shear rates necessary for platelet aggregation (PA), as well as the initial rate and the maximum extent of PA in citrated PRP.PA is quantified photometrically as a function of variable shear rates. The initial rate of PA steadily increases with increasing shear rates up to 460 sec-1. However, the maximal extent of PA (indicating the mechanical integrity of formed aggregates) saturates at about 35 sec-1 and then decreases because of a destruction of formed aggregates and of prevention of further PA. The aggregability of the platelets, as reflected by various degrees of shape changes, is enhanced by a drop of temperature and a rise in pH as well as by the so called aggregating agents (e.g. epinephrine 10-6 up to 10-9 M/l) : consecutively lower shear rates (lower effects of collision) are necessary to induce PA. In citrated PRP stable platelet aggregates are produced only within a defined range of shear rates. Platelet aggregability and aggregate stability are independent variables influenced by different experimental conditions.

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Tuning nonlinear damping in graphene nanoresonators by parametric–direct internal resonance

Nature Communications ◽

10.1038/s41467-021-21334-w ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Ata Keşkekler ◽

Oriel Shoshani ◽

Martin Lee ◽

Herre S. J. van der Zant ◽

Peter G. Steeneken ◽

...

Keyword(s):

Parametric Resonance ◽

Internal Resonance ◽

Microscopic Theory ◽

Fold Increase ◽

Nonlinear Damping ◽

Supporting Evidence ◽

Nonlinear Dissipation ◽

Modal Interactions ◽

Solid State Physics ◽

Internal Resonances

AbstractMechanical sources of nonlinear damping play a central role in modern physics, from solid-state physics to thermodynamics. The microscopic theory of mechanical dissipation suggests that nonlinear damping of a resonant mode can be strongly enhanced when it is coupled to a vibration mode that is close to twice its resonance frequency. To date, no experimental evidence of this enhancement has been realized. In this letter, we experimentally show that nanoresonators driven into parametric-direct internal resonance provide supporting evidence for the microscopic theory of nonlinear dissipation. By regulating the drive level, we tune the parametric resonance of a graphene nanodrum over a range of 40–70 MHz to reach successive two-to-one internal resonances, leading to a nearly two-fold increase of the nonlinear damping. Our study opens up a route towards utilizing modal interactions and parametric resonance to realize resonators with engineered nonlinear dissipation over wide frequency range.

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Vibration Characteristics of Hot Rolling Mill Rolls Based on Elastoplastic Hysteretic Deformation

Metals ◽

10.3390/met11060869 ◽

2021 ◽

Vol 11 (6) ◽

pp. 869

Author(s):

Rongrong Peng ◽

Xingzhong Zhang ◽

Peiming Shi

Keyword(s):

Hot Rolling ◽

Internal Resonance ◽

Rolling Mill ◽

Rolling Force ◽

Subharmonic Resonance ◽

Force Model ◽

Maximum Lyapunov Exponent ◽

Vibration System ◽

Hot Rolling Mill ◽

Rolling Mill Vibration

Based on the analysis of the influence of roll vibration on the elastoplastic deformation state of a workpiece in a rolling process, a dynamic rolling force model with the hysteresis effect is established. Taking the rolling parameters of a 1780 mm hot rolling mill as an example, we analyzed the hysteresis between the dynamic rolling force and the roll vibration displacement by varying the rolling speed, roll radius, entry thickness, front tension, back tension, and strip width. Under the effect of the dynamic rolling force and considering the nonlinear effect between the backup and work rolls as well as the structural constraints on the rolling mill, a hysteretic nonlinear vertical vibration model of a four-high hot rolling mill was established. The amplitude-frequency equations corresponding to 1/2 subharmonic resonance and 1:1 internal resonance of the rolling mill rolls were obtained using a multi-scale approximation method. The amplitude-frequency characteristics of the rolling mill vibration system with different parameters were studied through a numerical simulation. The parametric stiffness and nonlinear stiffness corresponding to the dynamic rolling force were found to have a significant influence on the amplitude of the subharmonic resonance system, the bending degree of the vibration curve, and the size of the resonance region. Moreover, with the change in the parametric stiffness, the internal resonance exhibited an evident jump phenomenon. Finally, the chaotic characteristics of the rolling mill vibration system were studied, and the dynamic behavior of the vibration system was analyzed and verified using a bifurcation diagram, maximum Lyapunov exponent, phase trajectory, and Poincare section. Our research provides a theoretical reference for eliminating and suppressing the chatter in rolling mills subjected to an elastoplastic hysteresis deformation.

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Symmetry-breaking bifurcations in resonant surface waves

Journal of Fluid Mechanics ◽

10.1017/s0022112089000455 ◽

1989 ◽

Vol 199 ◽

pp. 495-518 ◽

Cited By ~ 82

Author(s):

Z. C. Feng ◽

P. R. Sethna

Keyword(s):

Normal Form ◽

Symmetry Breaking ◽

Surface Waves ◽

Bifurcation Analysis ◽

Internal Resonance ◽

Travelling Waves ◽

Chaotic Behaviour ◽

Derived Set ◽

Parameter Values ◽

Theoretical Results

Surface waves in a nearly square container subjected to vertical oscillations are studied. The theoretical results are based on the analysis of a derived set of normal form equations, which represent perturbations of systems with 1:1 internal resonance and with D4 symmetry. Bifurcation analysis of these equations shows that the system is capable of periodic and quasi-periodic standing as well as travelling waves. The analysis also identifies parameter values at which chaotic behaviour is to be expected. The theoretical results are verified with the aid of some experiments.

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Internal resonance in a parametrically excited two-degree-of-freedom system with nonlinear spring characteristics. (2nd report, On the combination type)

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.52.657 ◽

1986 ◽

Vol 52 (474) ◽

pp. 657-663

Author(s):

Yukio ISHIDA ◽

Toshio YAMAMOTO

Keyword(s):

Internal Resonance ◽

Degree Of Freedom ◽

Parametrically Excited ◽

Nonlinear Spring ◽

Two Degree Of Freedom

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Observations of an internal resonance in a fjord

Journal of Marine Research ◽

10.1357/002224084788520783 ◽

1984 ◽

Vol 42 (4) ◽

pp. 873-891 ◽

Cited By ~ 5

Author(s):

J. R. Keeley

Keyword(s):

Internal Resonance

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Nonlinear Vibrations in a 2-Dimensional Protein Cluster Model with Linear Bonds

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.2000.214.1.065 ◽

2000 ◽

Vol 214 (1) ◽

Cited By ~ 9

Author(s):

E.G. Shidlovskaya ◽

L. Schimansky-Geier ◽

Yu.M. Romanovsky

Keyword(s):

Active Site ◽

Internal Resonance ◽

Cluster Model ◽

Active Sites ◽

Nonlinear Vibrations ◽

Nonlinear Phenomena ◽

Two Dimensional ◽

Dimensional Model ◽

Two Dimensional Model

A two dimensional model for the substrate inside a pocket of an active site of an enzyme is presented and investigated as a vibrational system. The parameters of the system are evaluated for α-chymotrypsin. In the case of internal resonance it is analytically and numerically shown that the energy concentrated on a certain degree of freedom might be several times larger than in the non-resonant case. Additionally, the system is driven by harmonic excitations and again energy due to nonlinear phenomena is redistributed inhomogeneously. These results may be of importance for the determination of the rates of catalytic events of substrates bound in pockets of active sites.

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