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Journal articles on the topic 'Oscillating behavior'

Author: Grafiati

Published: 2 June 2025

Last updated: 5 July 2025

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Li, Xiuchen, Jie Li, Zhaohui Zheng, Jinni Deng, Yi Pan, and Xiaobin Ding. "A self-oscillating gel system with complex dynamic behavior based on a time delay between the oscillations." Soft Matter 18, no. 3 (2022): 482–86. http://dx.doi.org/10.1039/d1sm01635k.

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A series of self-oscillating gels with different cross-linking densities are designed and fabricated. Due to the time delay between chemical and mechanical oscillation, they exhibit different oscillating behaviors. The disrupted mechanical oscillations tend to be regular and periodic under inhibited conditions.

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Rana, Zibaei, Sadegh Zakerhamidi Mohammad, Korram Sirous, and Ranjkesh Amid. "Effects of polarized light on the optical and self-oscillation behaviors of liquid crystal network polymers." Journal of Materials Chemistry C 9, no. 41 (2021): 14908–15. https://doi.org/10.1039/D1TC03870B.

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The phenomenon of self-oscillation is abundant in nature, which often occurs in response to various environmental stimuli. The most common stimuli for these processes are heat and light. Oscillations based on bending are one type of self-oscillating phenomenon. In this study, oscillations frequency and amplitude of liquid crystalline polymer network (LCN) structures with light are investigated. Due to the anisotropy of LCN, which originates from a specific orientation in the LCN surfaces, all studies are performed with polarized light to accurately determine the effect of different orientations of these networks on frequency and oscillation parameters. The different polarizations of light show different oscillating behaviors in terms of amplitude and frequency of the LCN oscillation. To investigate the factors affecting the amplitude and frequency, such as temperature and optical behaviors, the effect of increasing the power of the polarized light source on the behavior of these materials is evaluated.

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Klimov, Alexandr V., and Akop V. Antonyan. "Research of features of oscillating process’ behavior in the nonlinear system of individual traction drive of an electrobus." Izvestiya MGTU MAMI 17, no. 1 (2023): 87–96. http://dx.doi.org/10.17816/2074-0530-115233.

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BACKGROUND: When a vehicle is in motion, self-oscillations which properties are dependent on slip rate in a contact patch may occur in the area of tire interaction with ground surface. Oscillations frequency will vary in dependence with value of wheel slip relative to ground surface. Soft self-oscillations are excited by variable set of initial conditions at full slip in traction and driven wheel rolling modes as well as in mixed braking mode with partial slip. Hard mode of self-oscillations occurs at full wheel slip in braking mode. These processes have a negative impact on the processes in electric drive and mechanical drivetrain reducing their efficiency and may cause damage of components. Oscillations in the system are excited by interaction forces of an elastic tire with ground surface featuring vertical oscillations due to elastic behavior of its interaction with road unevenness. AIMS: Research of features of oscillating process behavior in the nonlinear system of individual traction drive of an electrobus. METHODS: Simulation of self-oscillation excitation processes in the area of contact interaction of a wheel and road was carried out in the MATLAB/Simulink software package. RESULTS: The article features the results of simulation and experimental studies of self-oscillation excitation processes of the KAMAZ 6282 electrobus moving on asphalt-concrete surface. It was found that vertical wheel displacement when moving through unevenness lead to oscillating behavior of vertical reaction forces in contact patches and, as a consequence, to oscillating behavior of longitudinal reaction forces, torque and rotation velocity of the shaft of the traction electric motor of the individual drive. It was defined that tire oscillation frequency is 67 Hz that coincides with electric motor shaft rotation oscillation frequency and this value is the same for both experiment and simulation. CONCLUSIONS: Practical value of the study lies in ability of using the study results at development of self-oscillation processes exclusion algorithms as a part of vehicle control system.

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Shi, Laishun, Jian Gao, and Jingjing Chen. "Modeling study for oscillatory reaction of chlorite – iodide – ethyl acetoacetate." Canadian Journal of Chemistry 92, no. 5 (2014): 417–25. http://dx.doi.org/10.1139/cjc-2014-0072.

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Chlorine dioxide based chemical oscillating behavior was modeled by a simple scheme consisting of three component reactions. Furthermore, little is known about the influence of the pH value. In this study, four component reactions were used to model the chlorite – iodide – ethyl acetoacetate oscillating reaction by dynamic analysis software. The oscillatory phenomenon is observed for concentration changes of triiodide ion, chlorite ion, and hydrogen ion. The initial concentration of ethyl acetoacetate, chlorite ion, iodide ion, and hydrogen ion has great influence on oscillations. The amplitude and number of oscillations are associated with the initial reactant concentrations. The equation of the reaction rate of triiodide ion, chlorite ion, or hydrogen ion changing with reaction time and initial concentrations in the oscillation stage was obtained. The bifurcation surface between oscillatory and nonoscillatory behavior with different pH values was obtained. The spatial zone for the occurrence of oscillation is reduced with an increase in the pH value. The range of oscillation as concentrations of chlorine dioxide, iodine, and ethyl acetoacetate is well described by an equation. There is a lower limit on ethyl acetoacetate initial concentration for oscillation. However, there is a higher limit on chlorine dioxide and iodine concentration for oscillation. The concentrations of chlorine dioxide and iodine for oscillation decrease with an increase in the pH value. The results provide new theoretical evidence of the importance of pH value, which can affect the bifurcation surface between oscillatory and nonoscillatory behavior.

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Scavuzzo, Rudolph J. "Oscillating Stress on Viscoelastic Behavior of Thermoplastic Polymers." Journal of Pressure Vessel Technology 122, no. 3 (2000): 386–89. http://dx.doi.org/10.1115/1.556197.

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Polymers are used in many applications where they are subjected to cyclic stresses. PVC and HDPE piping are often used in systems that include rotating machinery that cause mechanical vibration. Recent testing of thermoplastics indicates that there may be a large effect on the viscoelastic strains of thermoplastics from oscillating stresses. Cyclic loading on the permanent set of cross-linked elastomers has been studied. Perhaps, as expected, the effect of the oscillating behavior is measurable. Two types of tests have been conducted. First, tensile tests on HDPE standard specimens were conducted where oscillating stresses were superimposed onto an initial static or mean stress. These measurements showed a rapid decrease in the oscillating stresses when compared to measurements when steady nonoscillating stresses are applied to the same type of specimen. In the second test series, pressurized HDPE piping was subject to oscillating bending stresses. Ratcheting of the hoop strains in the pipe occurs. Results show that these strains follow the constitutive relationships of linear viscoelasticity and experimental results imply that viscoelastic changes are accelerated by stress oscillations. These preliminary results seem to indicate that the effects of oscillating stresses on the viscoelastic behavior of thermoplastics may be significant. A systematic study is required to further understand this behavior. [S0094-9930(00)02403-3]

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LI, QIAN SHU, and RUI ZHU. "MESOSCOPIC DESCRIPTION OF CHEMICAL SUPERCRITICAL HOPF BIFURCATION." International Journal of Bifurcation and Chaos 14, no. 07 (2004): 2393–97. http://dx.doi.org/10.1142/s0218127404010643.

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The mesoscopic dynamic behavior of the Oregonator model of the Belousov–Zhabotinsky chemical reaction is investigated as the model system experiences a supercritical Hopf bifurcation from focus to limit cycle oscillation. The study is performed by stochastically simulating the corresponding chemical master equation. Comparing the mesoscopic dynamic results with those obtained by the macroscopic dynamics, we find in the mesoscopic description a new type of oscillating state, in which large-amplitude oscillations and small-amplitude oscillations appear randomly alternately. This new state comes out spontaneously within a certain region called Hopf bifurcation range by us. In the mesoscopic description, the Hopf bifurcation point cannot be shown, being replaced by a Hopf bifurcation range. Furthermore, the applications of this new oscillating state to internal signal stochastic resonance are pointed out.

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De la Sen, M. "Oscillatory Behavior in Linear Difference Equations under Unmodeled Dynamics and Parametrical Errors." Mathematical Problems in Engineering 2007 (2007): 1–18. http://dx.doi.org/10.1155/2007/25692.

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This paper investigates the presence of oscillating solutions in time-varying difference equations even in the case when there exist parametrical errors (i.e., errors in the sequences defining their coefficients) and/or unmodeled dynamics, namely, the current order is unknown and greater than the nominal known order. The formulation is related to the concepts of conjugacy, disconjugacy, positivity, and generalized zeros and general conditions of oscillation are obtained both over particular intervals and for the whole solution. Some results concerned with the presence of stable oscillations are also presented.

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Lizunov, Petro, and Valentyn Nedin. "Transmission shafts vibrations in transient rotating modes." Strength of Materials and Theory of Structures, no. 110 (June 26, 2023): 229–37. http://dx.doi.org/10.32347/2410-2547.2023.110.229-237.

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The paper presents the investigation results of the transmission shaft dynamic behavior in transient modes of motion with change of the rotational speeds. Such modes occur during the transmission shaft transmits torque from engine to executive device. This process can be accompanied by vibration with change of frequency and amplitude of shaft oscillation. Therefore, the question of studying the dynamic behavior of such systems with identifying the impact of rotational speeds changing on them is relevant. In this regard, the study was done by developed software, in which a technique of computer simulation of the oscillating motion of considerable rotating rods under the action of inertia forces is implemented. Such software gives the possibility to model the oscillatory motion of rotating rods and determine the parameters by which the dynamic stability loss of the studying system can occur. Using this software, the diagrams of rod oscillating motion of the rotating shaft were drawn for definite parameters of the considered system. The process of oscillation is considered in space. The mathematical model of transverse oscillations is described by system of differential equations in rotating coordinate system that is tied to the shaft, but diagrams of oscillations is shown in inertial coordinate system. It is shown that when the speed of rotation changes, namely at the time interval of its increase, this process continues with growth of oscillation frequency during the acceleration time. Also shown that the amplitude of oscillations increases, too. After pass to next constant speed of rotation, the frequency of oscillations, as shown in diagrams, decreases back. Such increase of oscillation frequency during the acceleration can lead to undesirable consequences of destructive nature.

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Juang, Jyh-Ching. "Stability and Motion Patterns of Two Interactive Oscillating Agents." Information 15, no. 7 (2024): 388. http://dx.doi.org/10.3390/info15070388.

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This paper investigates the stability and motion of two interactive oscillating agents. Multiple agents can be controlled in a centralized and/or distributed manner to form specific patterns in cooperative tracking, pursuit, and evasion games, as well as environmental exploration. This paper studies the behavior of two oscillating agents due to their interaction. It shows that, through a combination of selecting oscillation centers and interaction gain, a variety of motions, including limit-cycles and stationary behavior, can be realized.

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Blasone, M., F. Giacosa, L. Smaldone, and G. Torrieri. "Flavor neutrinos as unstable particles: an interaction picture view." Journal of Physics: Conference Series 2883, no. 1 (2024): 012012. http://dx.doi.org/10.1088/1742-6596/2883/1/012012.

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Abstract This paper reviews the similarities in the behavior of unstable particles and oscillating neutrinos using perturbation theory within the interaction picture of quantum field theory. We begin by examining how decaying systems are studied in the interaction picture and then demonstrate how similar calculations can be performed to determine the transition probabilities for flavor oscillations. Notably, the expressions for neutrino oscillations and particle decays are identical in the short-time range. Furthermore, we show that the flavor oscillation formula derived through this method matches, within the adopted approximation, the one obtained using the flavor Fock space approach.

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Zheng, L., J. L. Plawsky, P. C. Wayner,, and S. DasGupta. "Stability and Oscillations in an Evaporating Corner Meniscus." Journal of Heat Transfer 126, no. 2 (2004): 169–78. http://dx.doi.org/10.1115/1.1652046.

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A Constrained Vapor Bubble Loop Thermosyphon, CVBLT, made of quartz was used to study the stability and oscillations of an evaporating curved wetting film of pentane in a corner. The film thickness profile was measured as a function of heat input, time, and axial position using image analyzing interferometry. The curvatures and apparent contact angles for the evaporating film under various operating conditions were obtained from the measured film thickness profiles. Instability (oscillation) of the liquid film was observed at relatively higher values of the heat input. The behavior of the curvature and the apparent contact angle of an oscillating film with changes in heat input was evaluated. Moving velocities of the oscillating film were calculated from the measured values of the liquid-wall wetted lengths and were found to be directly proportional to the difference between the instantaneous force acting on the curved film and the reference force. Using an augmented Young-Laplace pressure jump model, the effect of the excess free energy at the contact line on the oscillations was demonstrated.

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Yeung, R. W., and M. Vaidhyanathan. "Flow Past Oscillating Cylinders." Journal of Offshore Mechanics and Arctic Engineering 115, no. 4 (1993): 197–205. http://dx.doi.org/10.1115/1.2920112.

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The phenomenon of vortex shedding by oscillating cylinders is a complex one. Its understanding is, however, of utmost importance in marine-related engineering, particularly in connection with motions of deep submersibles and marine risers. In this paper, computational results are presented so that the behavior of the shedding as a function of certain parameter space can be elucidated. A methodology based on the random vortex method and a complex-variable boundary-integral formulation is used to study both forced and vortex-induced oscillations of a circular cylinder. Preliminary evaluation of this method indicates that it has been successful in predicting a number of experimentally observed behavior, among which the phenomena of “lock-in” associated with oscillations of the cylinder are well captured.

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Wakeland, Ray Scott, and Robert M. Keolian. "Measurements of Resistance of Individual Square-Mesh Screens to Oscillating Flow at Low and Intermediate Reynolds Numbers." Journal of Fluids Engineering 125, no. 5 (2003): 851–62. http://dx.doi.org/10.1115/1.1601254.

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Measurements are reported of pressure losses across single screens subjected to low-frequency oscillating flow for 0.002≲Red≲400, where Red is Reynolds number based on wire diameter and peak approach velocity. Several correlation methods are examined. Extensive comparisons are made between present oscillating-flow results and previous reports of the resistance of screens to steady flow. Defining oscillating results in terms of peak amplitudes, the oscillating and steady-flow resistances are found to be the same, including behavior in the intermediate Reynolds number region that departs from correlations of the form ARe−1+B. The friction factor is also found to depend on Reynolds number, but not independently on oscillation amplitude, over the range of conditions measured.

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Pustan, Marius, Corina Birleanu, Florina Rusu, and Simion Haragâş. "Dynamic Behavior of MEMS Resonators." Applied Mechanics and Materials 658 (October 2014): 694–99. http://dx.doi.org/10.4028/www.scientific.net/amm.658.694.

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MEMS resonator represents currently one of the important research areas of Microelectromechanical Systems (MEMS). The usual applications of MEMS resonators are the radio-frequency electromechanical devices, MEMS gyroscopes and resonant sensors. The main part of a MEMS resonator is the mechanical vibrating structure that can be fabricated as microcantilevers, microbridges or in a more complex configuration as micromembranes. The scope of this paper is to investigate the dynamic behavior of an electrostatically actuated MEMS cantilever under different oscillating modes in order to determine the resonant frequency, amplitude and velocity of oscillations. Moreover, based on the resonant frequency experimental curves, the quality factor for different oscillating modes is determined. The effect of operating conditions on the frequency response of investigated microcantilever is monitored. As a consequence, the experimental tests are performed both in ambient conditions and in vacuum. The dynamic response of microcantilever in vacuum is influenced by the intrinsic dissipation energy and the sample behavior in air depends on the intrinsic losses as well as the extrinsic dissipation energy.

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Prosperetti, Andrea. "Transient behavior of oscillating bubbles." Journal of the Acoustical Society of America 80, S1 (1986): S59. http://dx.doi.org/10.1121/1.2023874.

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Zholkovskij, E. K., V. I. Kovalchuk, V. B. Fainerman, et al. "Resonance Behavior of Oscillating Bubbles." Journal of Colloid and Interface Science 224, no. 1 (2000): 47–55. http://dx.doi.org/10.1006/jcis.1999.6669.

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Slabka, Iryna, Sören Henniger, David Kücükkaya, Michael Dawoud, and Hubert Schwarze. "Influence of Rheological Properties of Lithium Greases on Operating Behavior in Oscillating Rolling Bearings at a Small Swivel Angle." Lubricants 10, no. 7 (2022): 163. http://dx.doi.org/10.3390/lubricants10070163.

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In this study, the behavior of greases during oscillating bearing operation with a small oscillation angle and high frequency was investigated. This mode of operation entails demands on the lubrication system that differ significantly from those for continuously rotating bearings. In order to determine the variables influencing the suitability of a lubricating grease for small angle oscillating operation, the grease samples were examined with particular regard to their rheological properties. The focus of this investigation was to find a relationship between the rheological parameters and the real behavior in the bearing. Therefore, rheological and physical parameters, which influence the long-term structural changes and lubrication conditions, were identified. For this purpose, the viscosity was measured over a wide shear-rate range. The storage and loss modulus, the work of deformation, and the adhesion force jump are also determined. Afterward, rotational transient flow measurements were performed. These allowed us to analyze the development of the shear stress over time, at a constant shear rate, and to examine the internal friction behavior by evaluating the energy density. Subsequently, grease-lubricated four-point bearings were used in component tests, while the frictional torque was measured. These bearings operated in oscillating motion. Moreover, the yield point of mechanically aged greases was measured and compared with that of fresh greases to examine the influence of the oscillating operation on the lubricant condition. Finally, correlations between grease composition, rheological measurements, and component tests were investigated. Thereby, parameters influencing the frictional behavior of greases in rolling bearings during oscillating operation at small swivel angles were identified.

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Berezansky, L., G. E. Chatzarakis, A. Domoshnitsky, and I. P. Stavroulakis. "Oscillations of Difference Equations with Several Oscillating Coefficients." Abstract and Applied Analysis 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/392097.

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We study the oscillatory behavior of the solutions of the difference equationΔx(n)+∑i=1mpi(n)x(τi(n))=0,n∈N0[∇xn-∑i=1mpinxσin=0, n∈N]where(pi(n)),1≤i≤mare real sequences with oscillating terms,τi(n)[σi(n)],1≤i≤mare general retarded (advanced) arguments, andΔ[∇]denotes the forward (backward) difference operatorΔx(n)=x(n+1)-x(n)[∇x(n)=x(n)-x(n-1)]. Examples illustrating the results are also given.

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Hooshmand, Nasrin, Justin A. Bordley, and Mostafa A. El-Sayed. "Breakdown of the Dipole-Dipole Approximation at Short Distances and Hot Spot Formation between a Pair of Silver Nanocubes." MRS Proceedings 1802 (2015): 19–24. http://dx.doi.org/10.1557/opl.2015.504.

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ABSTRACTAg or Au nanocubes are known to be plasmonic nanoparticles with strong plasmonic fields concentrated around their corners1. When these nanoparticles aggregate the individual plasmonic oscillations of each particle begin to couple. The coupling between the two plasmonic nanoparticles is assumed to be dipolar in nature which results in an exponential red shift dependence of their localized surface plasmon resonance (LSPR) on the dimer separation2. Unfortunately, this exponential behavior is shown to fail as the separation distance between the two 42 nm nanocube dimer becomes 6nm or smaller3. Hooshmand et al4 have noted that these separation distances are marked by the formation of hot spots between the facets of the dimer.This dipolar exponential behavior results from a treatment of the coupling between the two excited nanocubes as a coupling between two oscillating dipole moments2. As a result, the vectorial addition of all the oscillating electronic dipoles is assumed to interact with the nearest nanoparticle as a single oscillating electronic dipole. Herein we suggest that as the separation distance becomes increasingly small, the coupling between the individual oscillating dipoles on the different nanocubes becomes significant. Thus, the dipolar exponential behavior fails to accurately predict the near field coupling between two nanoparticles with small separation distances.This leads to the realization that the interaction between the individual oscillating dipoles on the two nanocubes changes in a complicated manner as a function of separation distance. At 2nm, a good fraction of the oscillating dipoles are between the adjacent facets of the nanocubes as well as between the the corners. While at 3 nm less are in between the two facets of the nanocubes and a larger portion are localized at the corners. Thus, the coupling is not only dependent on the separation distance but also on what the separation does to the net interaction between the oscillating dipoles on each facet of the two coupled nanocubes. This results in the failure of the exponential behavior as the dipole moment on each nanocube is changing with distance in a complicated manner.

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Fahrbach, Michael, Min Xu, Wilson Ombati Nyang’au, et al. "Damped Cantilever Microprobes for High-Speed Contact Metrology with 3D Surface Topography." Sensors 23, no. 4 (2023): 2003. http://dx.doi.org/10.3390/s23042003.

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We addressed the coating 5 mm-long cantilever microprobes with a viscoelastic material, which was intended to considerably extend the range of the traverse speed during the measurements of the 3D surface topography by damping contact-induced oscillations. The damping material was composed of epoxy glue, isopropyl alcohol, and glycerol, and its deposition onto the cantilever is described, as well as the tests of the completed cantilevers under free-oscillating conditions and in contact during scanning on a rough surface. The amplitude and phase of the cantilever’s fundamental out-of-plane oscillation mode was investigated vs. the damping layer thickness, which was set via repeated coating steps. The resonance frequency and quality factor decreased with the increasing thickness of the damping layer for both the free-oscillating and in-contact scanning operation mode, as expected from viscoelastic theory. A very low storage modulus of E′≈100kPa, a loss modulus of E″≈434kPa, and a density of ρ≈1.2gcm−3 were yielded for the damping composite. Almost critical damping was observed with an approximately 130 µm-thick damping layer in the free-oscillating case, which was effective at suppressing the ringing behavior during the high-speed in-contact probing of the rough surface topography.

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Xu, Ran, Xiaoming Yang, and Siquan Tian. "Use of Space-Time Cube Model and Spatiotemporal Hot Spot Analyses in Fisheries—A Case Study of Tuna Purse Seine." Fishes 8, no. 10 (2023): 525. http://dx.doi.org/10.3390/fishes8100525.

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Katsuwonus pelamis, or skipjack, is a vital resource in purse seine fishing across the Central and Western Pacific. Identifying skipjack distribution hotspots and coldspots is crucial for effective resource management, but the dynamic nature of fish behavior means these spots are not constant. We used Chinese fishing logbook data from 2010 to 2019 to analyze skipjack resource hotspots and coldspots in a space-time cube. The study revealed 13 spatiotemporal patterns in skipjack Catch per Unit Effort (CPUE). Hotspots (36.53%) were concentrated in the central area, predominantly showing oscillating hotspots (21.25%). The significant effect of the eastern oscillating hotspot continues to be enhanced and extends to the east. Coldspots constituted 63.47% of the distribution, mainly represented by intensifying coldspots (25.07%). The no-pattern-detected type (10.53%) is distributed between coldspots and hotspots. The fishing grounds exhibited longitudinal oscillations of 3°–6° and latitudinal oscillations of 1°–2°. The spatial autocorrelation of cold and hot spot distribution was strong, and the spatiotemporal dynamic changes in skipjack resources were closely related to the El Niño-Southern Oscillation (ENSO) phenomenon. Notably, during 2011–2016, hotspots exhibited an eastward expansion trend, which continued from 2017–2019 due to the influence of fishery management measures, such as the Vessel Day Scheme (VDS) system.

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Richards, G. A., and M. C. Janus. "Characterization of Oscillations During Premix Gas Turbine Combustion." Journal of Engineering for Gas Turbines and Power 120, no. 2 (1998): 294–302. http://dx.doi.org/10.1115/1.2818120.

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The use of premix combustion in stationary gas turbines can produce very low levels of Nox emissions. This benefit is widely recognized, but turbine developers routinely encounter problems with combustion oscillations during the testing of new premix combustors. Because of the associated pressure fluctuations, combustion oscillations must be eliminated in a final combustor design. Eliminating these oscillations is often time-consuming and costly because there is no single approach to solve an oscillation problem. Previous investigations of combustion stability have focused on rocket applications, industrial furnaces, and some aeroengine gas turbines. Comparatively little published data is available for premixed combustion at conditions typical of an industrial gas turbine. In this paper, we report experimental observations of oscillations produced by a fuel nozzle typical of industrial gas turbines. Tests are conducted in a specially designed combustor capable of providing the acoustic feedback needed to study oscillations. Tests results are presented for pressure up to 10 atmospheres, with inlet air temperatures up to 588 K (600 F) burning natural gas fuel. Based on theoretical considerations, it is expected that oscillations can be characterized by a nozzle reference velocity, with operating pressure playing a smaller role. This expectation is compared to observed data that shows both the benefits and limitations of characterizing the combustor oscillating behavior in terms of a reference velocity rather than other engine operating parameters. This approach to characterizing oscillations is then used to evaluate how geometric changes to the fuel nozzle will affect the boundary between stable and oscillating combustion.

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Botros, K. K., G. H. Dunn, and J. A. Hrycyk. "Riser-Relief Valve Dynamic Interactions (Extension to a Previous Model)." Journal of Pressure Vessel Technology 120, no. 2 (1998): 207–12. http://dx.doi.org/10.1115/1.2842242.

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Further investigation of the dynamic stability behavior of a typical pilot-operated relief valve is reported. The present study is an extension to Botros et al. (1997) model, which includes mapping of the oscillating frequencies and amplitudes with riser dimensionless length L/D; inclusion of the effects of a wedge-O-ring seal in the model; detailed analyses of the field tests revealing unknown values for model parameters. These model refinements resulted in a better agreement between simulation results and field measurements. Analysis of piston oscillation frequencies and amplitudes indicates that the piston oscillation frequency mirrors the riser’s one-quarter-wave resonance frequency for lower values of L/D. At L/D = 20 and higher, two modes of oscillations started to emerge with two distinct frequencies. Maximum oscillation amplitudes occurred at L/D corresponding to one-quarter wave. Wedge-O-ring seal mechanism helps in suppressing piston oscillations; but it must be used in conjunction with a proper lubricant, otherwise the piston may jam partway during the upward stroke.

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Heerebout, Bram T., and R. Hans Phaf. "Emergent Oscillations in Evolutionary Simulations: Oscillating Networks Increase Switching Efficacy." Journal of Cognitive Neuroscience 22, no. 5 (2010): 807–23. http://dx.doi.org/10.1162/jocn.2009.21205.

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LeDoux [LeDoux, J. E. The emotional brain. New York: Simon & Schuster, 1996] motivated the direct route in his dual-pathway model by arguing that the ability to switch rapidly between different modes of behavior is highly adaptive. This motivation was supported by evolutionary simulations [den Dulk, P., Heerebout, B. T., & Phaf, R. H. A computational study into the evolution of dual-route dynamics for affective processing. Journal of Cognitive Neuroscience, 15, 194–208, 2003], in which foraging agents, controlled by simple inheritable neural networks, navigated an artificial world while avoiding predation. After many generations, a dual-processing architecture evolved that enabled a rapid switch to avoidance behavior when a predator appeared. We added recurrent connections to a new “context” layer in the indirect pathway to provide the agents with a working memory of previous input (i.e., a “context”). Unexpectedly, agents with oscillating networks emerged that had a much higher fitness than agents without oscillations. Oscillations seemed to have similar effects on switching speed as the dual-processing architecture, but they enhanced switching efficacy to a much larger degree. There has been much neurobiological speculation on the function, if any, of neural oscillations. These findings suggest that the facilitation of switching behavior is a likely candidate. Moreover, the strongly improved adaptation in the simulations contradicts the position that neural oscillations are merely a by-product of cell firing and have no functional value [Pareti, G., & De Palma, A. Does the brain oscillate? The dispute on neuronal synchronization. Neurological Sciences, 25, 41–47, 2004].

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Tilger, Christopher F., Joseph D. Olles, and Amir H. Hirsa. "Phase behavior of oscillating double droplets." Applied Physics Letters 103, no. 26 (2013): 264105. http://dx.doi.org/10.1063/1.4858487.

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ZEBBAR, Djallel, Kouider MOSTEFA, Sahraoui KHERRIS, and Guillaume HOUZEAUX. "THE HIGHLIGHTING OF AN INTERNAL COMBUSTION ENGINE PISTON RING RADIAL OSCILLATIONS." Recueil de mécanique 1, no. 1 (2016): 7–16. https://doi.org/10.5281/zenodo.1134917.

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This paper deals with the definition of the lube-oil film thickness in the piston ring cylinder liner junction of an internal combustion engine. At first, a mathematical model for the estimation of the film thickness is established. It is used to point out the oscillating motion of the piston ring normal to the cylinder wall. For the first time, has been highlighted and analytically evaluated the oscillating behavior of the piston ring in its housing in the radial direction. Furthermore, it is demonstrated that the radial oscillations frequency is a function of piston ring stiffness, material and geometry.

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Pariz, Aref, Ingo Fischer, Alireza Valizadeh, and Claudio Mirasso. "Transmission delays and frequency detuning can regulate information flow between brain regions." PLOS Computational Biology 17, no. 4 (2021): e1008129. http://dx.doi.org/10.1371/journal.pcbi.1008129.

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Brain networks exhibit very variable and dynamical functional connectivity and flexible configurations of information exchange despite their overall fixed structure. Brain oscillations are hypothesized to underlie time-dependent functional connectivity by periodically changing the excitability of neural populations. In this paper, we investigate the role of the connection delay and the detuning between the natural frequencies of neural populations in the transmission of signals. Based on numerical simulations and analytical arguments, we show that the amount of information transfer between two oscillating neural populations could be determined by their connection delay and the mismatch in their oscillation frequencies. Our results highlight the role of the collective phase response curve of the oscillating neural populations for the efficacy of signal transmission and the quality of the information transfer in brain networks.

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Zhang, Hailong, Enrong Wang, Fuhong Min, Ning Zhang, Chunyi Su, and Subhash Rakheja. "Nonlinear Dynamics Analysis of the Semiactive Suspension System with Magneto-Rheological Damper." Shock and Vibration 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/971731.

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This paper examines dynamical behavior of a nonlinear oscillator which models a quarter-car forced by the road profile. The magneto-rheological (MR) suspension system has been established, by employing the modified Bouc-Wen force-velocity (F-v) model of magneto-rheological damper (MRD). The possibility of chaotic motions in MR suspension is discovered by employing the method of nonlinear stability analysis. With the bifurcation diagrams and corresponding Lyapunov exponent (LE) spectrum diagrams detected through numerical calculation, we can observe the complex dynamical behaviors and oscillating mechanism of alternating periodic oscillations, quasiperiodic oscillations, and chaotic oscillations with different profiles of road excitation, as well as the dynamical evolutions to chaos through period-doubling bifurcations, saddle-node bifurcations, and reverse period-doubling bifurcations.

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CAMPÀS, O., C. LEDUC, P. BASSEREAU, J. F. JOANNY, and J. PROST. "COLLECTIVE OSCILLATIONS OF PROCESSIVE MOLECULAR MOTORS." Biophysical Reviews and Letters 04, no. 01n02 (2009): 163–78. http://dx.doi.org/10.1142/s1793048009000971.

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We present both a theoretical and an experimental study of the long time behavior of membrane nanotubes pulled from giant unilamellar vesicles by molecular motors. Experimentally, two types of behaviors are observed, either tubes stall at a finite length or they undergo periodic oscillations. Theoretically we write the equations for the tube dynamics as a two-dimensional dynamical system where the variables are the tube length (or the force required to pull the tube at a given length) and the number of motors at the tip pulling the tube. We construct stability diagrams showing the stalling and oscillating states and present an example of oscillations in a non-linear regime. These results can explain the membrane tube retractions and oscillations observed in living cells.

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Baptista, C. A., M. P. Ramos, and C. H. de Jesus. "Correlation between damping coefficients and externally injected currents in oscillations produced by lithium ions in frog skin." Journal of Experimental Biology 135, no. 1 (1988): 51–64. http://dx.doi.org/10.1242/jeb.135.1.51.

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Oscillations in the electrical parameters elicited by Li+ added to the mucosal side of frog skin in vitro were studied under different experimental conditions. The correlation between the damping coefficient and the size of the externally injected current was ascertained. The size of the overall epithelial resistance in NaCl-Ringer seems to be a good indicator of the qualitative behaviour of the skin in the presence of Li+: the higher the resistance the less probable the occurrence of oscillations. Addition of amiloride allowed the calculation of the electromotive force in Na+- and Li+-Ringer. Calculations of the ‘total equivalent inductance’ and ‘total equivalent capacitance’ of an oscillating skin were made using resistance values (R), damping coefficients (sigma) and frequency of oscillation (omega).

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Masuda, Tsukuru, Ayako Terasaki, Aya Mizutani Akimoto, Kenichi Nagase, Teruo Okano, and Ryo Yoshida. "Control of swelling–deswelling behavior of a self-oscillating gel by designing the chemical structure." RSC Advances 5, no. 8 (2015): 5781–87. http://dx.doi.org/10.1039/c4ra10675j.

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To improve the self-oscillating gel we have developed so far, the ternary self-oscillating polymer and the gel were newly prepared. Their phase transition and self-oscillating behaviors were investigated considering potential applications.

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Aoki, Reiko, Manabu Enoki, and Ryo Yoshida. "Mechanical Behavior during Self-Oscillating of NIPAAm-Co-(Ru(bpy)₃ Gel." Key Engineering Materials 353-358 (September 2007): 2235–38. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2235.

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Self-oscillating gel is designed by copolymerizing the catalyst for the Belousov-Zhabotinsky (BZ) reaction with thermosensitive polymer. The cylindrical-shaped specimens of NIPAAm-co-(Ru(bpy)3 gel were prepared by copolymerizing (Ru(bpy)3) monomer as catalyst with NIPAAm as thermosensitive polymer. Swelling behavior during self-oscillating of gel by BZ reaction was observed using CCD camera and the force due to this reaction was evaluated using semiconductor gauge. Self-oscillating swelling-deswelling behavior in samples with different swelling ratio was evaluated by this apparatus, and mechanical parameters such as Young’s modulus, stress amplitude and oscillating period were quantitatively estimated.

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Hara, Yusuke, and Rumana A. Jahan. "Self-Oscillating Behaviors of Negatively Charged Polymer Chain Induced by the Belousov-Zhabotinsky Reaction." Advanced Materials Research 181-182 (January 2011): 206–11. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.206.

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In this paper, we studied the effect of the temperature and the initial concentration of sodium bromate (NaBrO3) on the aggregation-disaggregation self-oscillation for a polymer chain. The polymer chain consisted of N-isopropylacrylamide (NIPAAm), Ru catalyst of the BZ reaction and Acrylamide-2-methylpropanesulfonic acid (AMPS) as a solubility control site. The concentration of sodium bromate and the temperature significantly affected the self-oscillating behavior and the period of the aggregation-disaggregation self-oscillation. Moreover, the amplitude of the aggregation-disaggregation self-oscillation of the AMPS-containing polymer solution decreased with time. The damping behavior is originating from the increase in the size of the polymer chain. In addition, this study clarified that the period of the self-oscillation of the AMPS-containing polymer solution in the strongly acidic condition was significantly shorter than that in the acid-free condition.

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GARDINI, LAURA, and RENZO LUPINI. "ONE-DIMENSIONAL CHAOS IN IMPULSED LINEAR OSCILLATING CIRCUITS." International Journal of Bifurcation and Chaos 03, no. 04 (1993): 921–41. http://dx.doi.org/10.1142/s0218127493000787.

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The dynamics of a damped linear oscillating circuit subject to impulses is represented by a one-dimensional endomorphism (or noninvertible map) π: ℝ → ℝ. The asymptotic behavior of orbits in the phase-plane is characterized in terms of critical points and point singularities of π (fixed points or cycles). Their combined effect, that is, the merging of a critical point into a repelling cycle, causes a global bifurcation or a homoclinic bifurcation, with transition to chaotic oscillations.

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Dzhunushaliev, Vladimir. "Higgs Field in Universe: Long-Term Oscillation and Deceleration/Acceleration Phases." Journal of Gravity 2014 (July 20, 2014): 1–6. http://dx.doi.org/10.1155/2014/326749.

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It is shown that the Einstein gravity and Higgs scalar field have (a) a long-term oscillation phase; (b) cosmological regular solutions with deceleration/acceleration phases. The first has a preceding contracting and subsequent expanding phases and between them there exists an oscillating phase with arbitrary time duration. The behavior of the second solution near to a flex point is in detail considered.

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STEINDL, ALOIS. "FAST OSCILLATIONS IN A SINGULARLY PERTURBED PRODUCTION MODEL." Mathematical Models and Methods in Applied Sciences 11, no. 01 (2001): 149–62. http://dx.doi.org/10.1142/s0218202501000805.

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We investigate the behavior of a production model with non-convex operating cost and small adaption cost for the production rate. For zero adaption cost the optimal solution is known to be a chattering strategy, oscillating infinitely fast between two efficient production speeds. We show that for small values of the adaption cost a fast oscillation between the two states occurs.

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Bathellier, Brice, Alan Carleton, and Wulfram Gerstner. "Gamma Oscillations in a Nonlinear Regime: A Minimal Model Approach Using Heterogeneous Integrate-and-Fire Networks." Neural Computation 20, no. 12 (2008): 2973–3002. http://dx.doi.org/10.1162/neco.2008.11-07-636.

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Fast oscillations and in particular gamma-band oscillation (20–80 Hz) are commonly observed during brain function and are at the center of several neural processing theories. In many cases, mathematical analysis of fast oscillations in neural networks has been focused on the transition between irregular and oscillatory firing viewed as an instability of the asynchronous activity. But in fact, brain slice experiments as well as detailed simulations of biological neural networks have produced a large corpus of results concerning the properties of fully developed oscillations that are far from this transition point. We propose here a mathematical approach to deal with nonlinear oscillations in a network of heterogeneous or noisy integrate-and-fire neurons connected by strong inhibition. This approach involves limited mathematical complexity and gives a good sense of the oscillation mechanism, making it an interesting tool to understand fast rhythmic activity in simulated or biological neural networks. A surprising result of our approach is that under some conditions, a change of the strength of inhibition only weakly influences the period of the oscillation. This is in contrast to standard theoretical and experimental models of interneuron network gamma oscillations (ING), where frequency tightly depends on inhibition strength, but it is similar to observations made in some in vitro preparations in the hippocampus and the olfactory bulb and in some detailed network models. This result is explained by the phenomenon of suppression that is known to occur in strongly coupled oscillating inhibitory networks but had not yet been related to the behavior of oscillation frequency.

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Hara, Yusuke, and Ryo Yoshida. "Control of Oscillating Behavior for the Self-Oscillating Polymer with pH-Control Site." Langmuir 21, no. 21 (2005): 9773–76. http://dx.doi.org/10.1021/la052070v.

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Alessio, Francesca, Vittorio Coti Zelati, and Piero Montecchiari. "Chaotic behavior of rapidly oscillating Lagrangian systems." Discrete & Continuous Dynamical Systems - A 10, no. 3 (2004): 687–707. http://dx.doi.org/10.3934/dcds.2004.10.687.

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Parkins, D. W., and J. H. Woollam. "Behavior of an Oscillating Oil Squeeze Film." Journal of Tribology 108, no. 4 (1986): 639–44. http://dx.doi.org/10.1115/1.3261292.

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This paper records observations of the behavior of an oil film subject to an oscillatory squeeze motion of its containing surfaces. In the experimental apparatus, the square upper surface oscillated at a frequency within the range 5–45 Hz and contained two pressure transducers. A fixed transparent lower surface facilitated viewing of cavitation patterns and their position relative to the pressure transducers. A computer controlled technique enabled these patterns to be photographed at any selected point in the oscillatory cycle, and synchronized with the corresponding instantaneous oil film pressure and thickness. The effect is given of vibratory amplitude, frequency and initial oil film thickness upon the steady force generated by the oscillatory squeeze motion. A previously identified cavitation regime has been shown to be more complex than hitherto supposed. Four sub-regimes have been tentatively identified. Their characteristics are described, together with photographs of typical sequences of cavitation patterns in each subregime, at identified times in the pressure and film thickness cycle. The effects of surrounding oil depth upon the vibratory amplitude at which cavitation first appears, is described. Descriptions are given of the sub-regime appearing at onset, and any changes thereto appearing with further increases in vibratory amplitude.

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Wu, S. Y., W. H. Li, K. C. Lee, and H. D. Yang. "Oscillating magnetic behavior in La1+xSr2−xMn2O7." Physica B: Condensed Matter 259-261 (January 1999): 839–40. http://dx.doi.org/10.1016/s0921-4526(98)00742-x.

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Fink, Anja, Oliver Nett, Simon Schmidt, et al. "Free Stream Behavior of Hydrogen Released from a Fluidic Oscillating Nozzle." Fluids 6, no. 7 (2021): 245. http://dx.doi.org/10.3390/fluids6070245.

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The H2 internal combustion engine (ICE) is a key technology for complete decarbonization of the transport sector. To match or exceed the power density of conventional combustion engines, H2 direct injection (DI) is essential. Therefore, new injector concepts that meet the requirements of a H2 operation have to be developed. The macroscopic free stream behavior of H2 released from an innovative fluidic oscillating nozzle is investigated and compared with that of a conventional multi-hole nozzle. This work consists of H2 flow measurements and injection tests in a constant volume chamber using the Schlieren method and is accompanied by a LES simulation. The results show that an oscillating H2 free stream has a higher penetration velocity than the individual jets of a multi-hole nozzle. This behavior can be used to inject H2 far into the combustion chamber in the vertical direction while the piston is still near bottom dead center. As soon as the oscillation of the H2 free stream starts, the spray angle increases and therefore H2 is also distributed in the horizontal direction. In this phase of the injection process, spray angles comparable to those of a multi-hole nozzle are achieved. This behavior has a positive effect on H2 homogenization, which is desirable for the combustion process.

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Guzev, Mikhail, and A. A. Dmitriev. "Heat flux in the Langevin model for two particles." Dal'nevostochnyi Matematicheskii Zhurnal 21, no. 1 (2021): 39–44. http://dx.doi.org/10.47910/femj202103.

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The analytical representation for the heat flux is obtained on the basis of the constructed solution in a one-dimensional harmonic model for two particles. At $t\rightarrow\infty$, the amplitude asymptotic behavior of the flow passing through the particle is shown to be determined by the temperature difference between the left and right heat reservoirs, between which the system is located. The dynamic behavior of the thermal characteristic is oscillating in time; its oscillation period is set by the parameter of the system.

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Araghizadeh, MS, MH Djavareshkian, and J. Rezaeepazhand. "Simulating aeroelastic response of a self-sustained oscillating rigid airfoil using a boundary oscillation method." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 11 (2020): 1811–24. http://dx.doi.org/10.1177/0954410020919622.

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The present study presents a new nonlinear unsteady aerodynamic model to investigate the aeroelastic behavior of a self-sustained oscillating rigid airfoil. Here the unsteady Euler equations are considered simulating inviscid compressible transonic flow over an oscillating airfoil. In regard to providing boundedness criteria, a high-order technique based on a normalized variable diagram scheme has been presented. Since using dynamic mesh for simulating flow over a dynamic airfoil is too complex and requires many computational efforts, the current paper proposes a nonorthogonal and static mesh with oscillation of flow boundary. The results are compared with both well-validated numerical methods and experimental data. A time-marching method is employed to determine system responses. The predicted flutter boundary for NACA0012 airfoil at different free-stream Mach numbers is in fair agreement with direct flutter tools of the Hopf bifurcation points. Finally, the influences of the center of mass and elastic axis position on the system aeroelastic behavior are examined.

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SCHUSTER, H. G., M. LE VAN QUYEN, M. CHAVEZ, J. KÖHLER, J. MAYER, and J. C. CLAUSSEN. "DYNAMICAL BEHAVIOR AND CONTROL OF COUPLED THRESHOLD ELEMENTS WITH SELF-INHIBITION." International Journal of Bifurcation and Chaos 19, no. 09 (2009): 3119–28. http://dx.doi.org/10.1142/s0218127409024694.

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Coupled threshold elements with self-inhibition display a phase transition to an oscillating state where the elements fire in synchrony with a period T that is of the order of the dead-time caused by self-inhibition. This transition is noise-activated and therefore displays strong collectively enhanced stochastic resonance. For an exponentially decaying distribution of dead-times the transition to the oscillating state occurs, coming from high noise temperatures, via a Hopf bifurcation and coming from low temperatures, via a saddle node bifurcation. The transitions can be triggered externally by noise and oscillating signals. This opens up new possibilities for controlling slow wave sleep.

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Lu, Xiaobin, and M. M. Khonsari. "An Experimental Study of Grease-Lubricated Journal Bearings Undergoing Oscillatory Motion." Journal of Tribology 129, no. 3 (2007): 640–46. http://dx.doi.org/10.1115/1.2736705.

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A series of experiments was performed to study the behavior of grease-lubricated journal bearings. The results reveal that an oscillatory bearing undergoes a transition from boundary, to mixed, and to hydrodynamic regime. Another distinct feature is friction hysteresis that occurs as a result of oscillation. In this paper, we examine the effect of load, oscillating frequency, and lubricant on the friction hysteresis loop.

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Smrčinová, Miroslava, Preben Graae Sørensen, Július Krempasky, and Peter Ballo. "Chaotic Oscillations in a Chloroplast System Under Constant Illumination." International Journal of Bifurcation and Chaos 08, no. 12 (1998): 2467–70. http://dx.doi.org/10.1142/s0218127498001984.

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We show that nonlinear, aperiodic oscillatory behavior can be observed in a chloroplast system by measuring the absorption of light. This behavior depends on illumination of the system with light which is absorbed by chlorophyll. The oscillations can be stopped by addition of acetone indicating that chemical reactions are involved. These observations confirm the role of photosynthesis. The effect of stirring and the statistics of the oscillating part of the spectrum suggest that the buoyancy of oxygen bubbles formed during photosynthesis is an important art of the mechanism.

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HANUSSE, PATRICK, VICENTE PEREZ-MUÑUZURI, and MONCHO GOMEZ-GESTEIRA. "RELAXATION BEHAVIOR AND PATTERN FORMATION IN REACTION-DIFFUSION SYSTEMS." International Journal of Bifurcation and Chaos 04, no. 05 (1994): 1183–91. http://dx.doi.org/10.1142/s0218127494000885.

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The notions of relaxation oscillation and hard excitation have been extensively used and early recognized as important qualitative features of many nonlinear systems. Nevertheless, there seems to exist so far no clear mathematical definitions of these notions. We consider the description of relaxation behavior in oscillating or excitable systems resulting from symmetry breaking of the rotational symmetry of the velocity vector field of the Hopf normal form. From symmetry considerations we detect the first terms responsible for the relaxation character of the phase dynamics in such systems and show that they provide a good general, if not universal, definition of the relaxation properties. We analyze their consequence in the modeling of spatiotemporal patterns such as spiral waves.

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Ge, Dali, Qingrui Hong, Xin Liu, and Haiyi Liang. "Self-Oscillation of Liquid Crystal Elastomer Fiber-Slide System Driven by Self-Flickering Light Source." Polymers 16, no. 23 (2024): 3298. http://dx.doi.org/10.3390/polym16233298.

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Self-oscillation, a control approach inspired by biological systems, demonstrates an autonomous, continuous, and regular response to constant external environmental stimuli. Until now, most self-oscillation systems have relied on a static external environment that continuously supplies energy, while materials typically absorb ambient energy only intermittently. In this article, we propose an innovative self-oscillation of liquid crystal elastomer (LCE) fiber-slide system driven by a self-flickering light source, which can efficiently regulate the energy input in sync with the self-oscillating behavior under constant voltage. This system primarily consists of a photo-responsive LCE fiber, a slider that includes a conductive segment and an insulating segment, a light source, and a conductive track. Using the dynamic LCE model, we derive the governing equation for the motion of the LCE fiber-slider system. Numerical simulations show that the LCE fiber-slide system under constant voltage exhibits two distinct motion phases, namely the stationary phase and the self-oscillation phase. The self-oscillation occurs due to the photo-induced contraction of the LCE fiber when the light source is activated. We also investigate the critical conditions required to initiate self-oscillation, and examine key system parameters influencing its frequency and amplitude. Unlike the continuous energy release from the static environmental field in most self-oscillation systems, our LCE fiber-slide self-oscillation system is driven by a self-flickering light source, which dynamically adjusts the energy input under a constant voltage to synchronize with the self-oscillating behavior. Our design features advantages such as spontaneous periodic lighting, a simple structure, energy efficiency, and ease of operation. It shows significant promise for dynamic circuit systems, monitoring devices, and optical applications.

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Efimov, Anton, Aleksej Shabunin, Vladimir Astakhov, and Astero Provata. "Chaotic dynamics of chemical reactions in low-dimensional substrates: mean-field and Monte-Carlo approaches." Izvestiya VUZ. Applied Nonlinear Dynamics 11, no. 2 (2003): 72–80. http://dx.doi.org/10.18500/0869-6632-2003-11-2-72-80.

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Complex reactive dynamics оn low-dimensional lattices is studied using mean-field model and Monte-Carlo simulation. We consider four-species cyclic chemical reactions оn one- аnd two-dimensional catalytic supports. The resulted mean-field model is conservative. Depending оn parameters it shows quasi-periodic оr chaotic oscillations. One-dimensional lattice does not demonstrate oscillating behavior due to the geometric restrictions. Lattice Monte-Carlo simulations оn two-dimensional lattices show locally emergence оf chaotic oscillations which are resulted from complex motions and interactions of clusters оf homogeneous species. The properties оf the oscillations depends оп the size оf the lattice.

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