The undisturbed damped oscillator does not explode

Mechanism of damped oscillation in microbubble coalescence

The damped glycolytic oscillation phenomenon occurring in starved cells of the yeast Saccharomyces cerevisiae (NBRC 0565) was characterization for application to a toxicity bioassay. S. cerevisiae was grown under semi-anaerobic conditions. The transient oscillations were observed photometrically as the time course of the fluorescent intensity of reduced pyridine nucleotide resulting from instantaneous addition of glucose to a cell suspension. In this study, simple and reproducible conditions inducing damped oscillations were obtained by modifying a literature method. For estimation of the wave shapes of the damped oscillations we used six indexes. To investigate the total reproducibility as the averaged relative standard deviation (RSD(av)) for the six indexes obtained from the wave shapes, the damped oscillations were induced under the optimum conditions and the RSD(av) values were calculated as 14% in a buffer cell suspension (n = 62) and 22% in a water cell suspension (n = 78). Finally, the effects of glucose concentration on the six indexes were examined, and all the indexes changed when the glucose concentration was changed. Excellent correlations were obtained between the index of oscillation-state time and the concentration of glucose in a buffer cell suspension (r = 0.9985, 0.5-250 mmol L(-1), 10 points) and in a water cell suspension (r = 0.9989, 2.5 micromol L(-1)-250 mmol L(-1), 12 points), respectively.

SUMMARY We calculate the magnetic perturbation that occurs near the inner core boundary when the conducting materials on either side of the boundary are displaced by translational oscillations of the inner core. The associated Lorentz forces and ohmic losses cause changes in the period and damping of the oscillations which may be detectable in gravity measurements. Estimates of these changes depend on the average value of the radial main field Br near the inner core boundary. The value of Br also affects the character of the magnetic disturbance in the fluid core. For Br 0.002T the perturbation is transmitted by Alfven waves. The most observable effects are associated with the damping of the oscillations. Typical values of the damping factor Q vary widely with Br, but may be as low as 2000. Since Q is extremely sensitive to the main magnetic field we suggest that observations of the inner core oscillations might be used to infer the average strength of the field near the inner core boundary. To facilitate the interpretation of the gravity measurements, we present analytical expressions for the effect of a magnetic field on the period and Q of inner core oscillations.

Decision letter: NF-κB oscillations translate into functionally related patterns of gene expression

IW And stars are a recently recognized group of dwarf novae which are characterized by a repeated sequence of brightening from a standstill-like phase with damping oscillations followed by a deep dip. Kimura et al. (2019, PASJ, submitted) recently proposed a model based on thermal-viscous disk instability in a tilted disk to reproduce the IW And-type characteristics. IM Eri experienced the IW And-type phase in 2018 and we recorded three cycles of the (damping) oscillation phase terminated by brightening. We identified two periods during the IW And-type state: 4–5 d small-amplitude (often damping) oscillations and a 34–43 d long cycle. This behavior is typical for an IW And-type star. The object gradually brightened within the long cycle before the next brightening, which terminated the (damping) oscillation phase. This observation agrees with the increasing disk mass during the long cycle predicted by the Kimura et al. model of thermal-viscous disk instability in a tilted disk. We did not, however, succeed in detecting negative superhumps, which are considered to be the signature of a tilted disk.

In the present paper an analysis of the continuous radiation from photosphere of the Sun at equilibrium temperature of it is carried out. The radiation is assumed due to quantum jumps of the electron, in a high density ionized semi-gaseous type material of the photosphere of the Sun, from its amplitude states considering types of damped frequency oscillations and eigen frequency damped oscillations analogous to that exit in a low density plasma with electron-molecule collisions (Nandedkar 2016) [8]. Damped and eigen frequency damped oscillations of the electron result due to density fluctuations of the chargecarriers with opposite signs in the body of the photosphere due to nuclear processes going deep in the core of the Sun. The density fluctuations alternatively builds up and withdraws a d.c. electric field in the body of the photosphere. The necessary damping for the type of damped oscillations mentioned, is provided by electron-ion collision type interaction at equilibrium temperature of the photosphere. The minimum value of the amplitude the electron takes which can be quantized in the field of the neighbouring ion and in the absence of the d.c. electric field when eigen-frequency damped oscillations result, govern the minimum value of the wavelength of radiation from the continuous spectrum of the photosphere. In general the wavelength is shown to be a function of the average density of the charge-carriers. Thus lower limit of the electron density corresponding to an intermediate value of the chromosphere, brings an upper limit for the radiation-wavelength of the radiation spectrum of the photosphere. The continuous radiation from photosphere of the Sun corresponds to electron density variations in the range \(4.774(2) \times 10^{29} \mathrm{~m}^{-3} \geq \mathrm{N}_{\mathrm{e}} \geq 1 \times 10^{16} \mathrm{~m}^{-3}\) corresponds to wavelength \(\lambda\) of radiation in the range 0.2476(8)×10-6 m\(\leq\) \(\lambda\) \(\leq\)8.984(9)×10-3 However recently the solar spectrum is photographed up to a wavelength of about 0.2099×10-6 m which can be explained due to a mixture of a doubly charged ion and a singly charged ion in right proportion with one of electrons in each cases be considered, then the average distance of the electron from the ion can tend to lower down the minimum value of radiation wavelength.

Rabi oscillations in the presence of dissipation are theoretically studied at finite temperatures. The system that we consider is a quantum two-level system with both internal relaxations and external decays under an alternating field. The environment modeled by a set consisting of an infinite number of harmonic oscillators is employed in order to introduce temperature into the system. The equations of motion for the density matrix (Liouville equation) of such a quantum two-level system coupled to a Caldeira-Leggett-type environment are obtained with the Born-Markov approximation. Internal relaxations of the system are incorporated into the Liouville equations using the Redfield theory, resulting in Liouville equations with temperature-dependent relaxation rates. The exact solutions are obtained by using the Torrey method based on the Laplace transform. The solution for damped Rabi oscillations can be divided into elementary relaxation processes such as a simple decay and a damped oscillation. Since the coefficients of the solution involve physical relaxation rates corresponding to the processes, all the relaxation rates such as the dephasing rate are determined by simple calculations of the coefficients in these different relaxation processes.

A dynamic model of the manipulator of the robotic complex was developed on the basis of the conducted experimental studies. The concept of determining the dynamic characteristics of the mechanical system is proposed according to the results of the oscillation analysis. The algorithm is supplemented with modules considering possibility of using controlled damping devices. The constituent parts of the model represent the mechanical devices of the manipulator, in particular connections, rotary assemblies and damping devices. The model contains all the connections between the modules, which allows you to study the dynamic parameters during the operation of the mechanism. Differential dependencies for the implementation of the mathematical model, which includes the subsystem of dynamic damping of vibrational oscillations of the manipulator, are proposed. These dependencies reveal the essence of the oscillatory processes of the mechanical system in full. Guided damping devices introduced into the model allow to control parameters in order to increase the accuracy of the mechanism. The mathematical model is implemented via a software module that takes into account the impact working processes that occur in the connections and rotary assemblies of the mechanical system of the robotic complex. The algorithm involves the use of a mechatronic system equipped with feedback sensors to control the manipulator. Controlled damping devices make it possible to increase the technical level and improve the dynamic characteristics of the mechanical system. Damping of oscillations by a mechatronic system with feedback was investigated and the influence of damping of oscillations on accuracy parameters when moving a robotic complex on an uneven surface was determined. The paper presents the results of modeling an adjustable damper as part of a moving mechanical system. The innovative device uses a magnetorheological fluid as a working fluid, which allows you to control it with the help of electrical impulses. The conducted experimental studies made it possible to obtain key indicators and its operating characteristics of the damper. Based on these results, dependencies, which determine the control laws of a damper that uses a magnetorheological fluid, are proposed.

Cell synchrony was investigated during glycolytic oscillations in starved yeast cell suspensions at cell densities ranging from 2 × 106-5 × 107cells ml-1. Oscillations in NAD(P)H were triggered by inhibition of mitochondrial respiration when intracellular NAD(P)H had reached a steady state after glucose addition. Before macroscopic damping of the oscillations, individual yeast cells oscillated in phase with the cell population. After oscillations had damped out macroscopically, a significant fraction of the cells still exhibited oscillatory dynamics, slightly out-of-phase. At cell concentrations higher than 107cells ml-1the dependence upon cell-density of (i) the damping of glycolytic oscillations and (ii) the amplitude per cell suggested that cell-to-cell interaction occurred. Most importantly, at cell densities exceeding 107cells ml-1the damping was much weaker. A combination of modelling studies and experimental analysis of the kinetics of damping of oscillations and their amplitude, with and without added ethanol, pyruvate or acetaldehyde, suggested that the autonomous glycolytic oscillations of the yeast cells depend upon the balance between oxidative and reductive (ethanol catabolism) fluxes of NADH, which is affected by the extracellular concentration of ethanol. Based on the facts that cell (i) excrete ethanol, (ii) are able to catabolize external ethanol, and (iii) that this catabolism affects their tendency to oscillate, we suggest that the dependence of the oscillations on cell density is mediated through the concentration of ethanol in the medium.

The beam oscillations are modeled by the fourth-order hyperbolic partial differential equation. The minimized functional is the energy integral of an oscillating beam. Control is implemented via certain function appearing in the right side of the equation. It was shown that the solution of the problem exists for any given damping time, but with decreasing this time, finding the optimal control becomes more complicated. In this work, numerical damping of beam oscillations is implemented via several fixed point actuators. Computational algorithms have been developed on the basis of the matrix sweep method and the second order Marquardt minimization method. To find a good initial approximation empirical functions with a smaller number of variables are used. Examples of damping the oscillations via a different number of actuators are given. It is shown that the amplitude of the oscillations of any control functions increases with the reduction of the given damping time. Examples of damping the oscillations in the presence of constraints on control functions are given; in this case, the minimum damping time exists. The damping of oscillations is considered also in the case when different combinations of actuators are switched on at different time intervals of oscillation damping.

This paper presents the effective control signals of Unified Power Flow Controller (UPFC) for damping of oscillations with Power Oscillation Damping Controller (POD) in Linearized Modified Phillips Heffron Model of Single Machine Infinite Bus System (SMIB). The POD parameters are optimized by using Nonlinear Control Design Blockset (NCD). The result indicate the significant improvement in damping of oscillations. Eigen value analysis validate the performance of various damping controllers.

Observations of transverse coronal loop oscillations very often show the excitation and damping of oscillations in groups of coronal loops rather than in individual and isolated structures. We present results on the oscillatory properties (periods, damping rates, and spatial distribution of perturbations) for resonantly damped oscillations in a system of two inhomogeneous coronal slabs and compare them to the properties found in single-slab loop models. A system of two identical coronal loops is modeled, in Cartesian geometry, as being composed of two density enhancements. The linear magnetohydrodynamic (MHD) wave equations for oblique propagation of waves are solved, and the damping of the different solutions, due to the transverse inhomogeneity of the density profile, is computed. The physics of the obtained results is analyzed by an examination of the perturbed physical variables. We find that, due to the interaction between the loops, the normal modes of oscillation present in a single slab split into symmetric and antisymmetric oscillations when a system of two identical slabs is considered. The frequencies of these solutions may differ from the single slab results when the distance between the loops is of the order of a few slab widths. Oblique propagation of waves weakens this interaction, since solutions become more confined to the edges of the slabs. The damping is strong for surface-like oscillations, while sausage body-like solutions are unaffected. For some solutions, and small slab separations, the damping in a system of two loops differs substantially from the damping of a single loop.

This paper considers damped rotational oscillations about the vertical axis of a cylindrical permanent magnet that is horizontally suspended by a vertical inelastic thread. The damping of the oscillations is caused by eddy currents induced in aluminum foil that is placed horizontally below the magnet. A simplified mathematical model of the damped oscillations is proposed and verified by experiment qualitatively and quantitatively. It is shown that the relative energy loss during one oscillation depends linearly on the number of layers of aluminum foil and on the oscillation period. To measure the relative changes of the oscillation amplitude, a magnetic field sensor and data collection interface are used.

Distributed Generation is a small source of electric power conversion from non-conventional energy sources such as Photo Voltaic system (PV), wind, Fuel cell etc. Small signal stability analysis is very much essential to study the inter-area and intra area oscillations which normally exist in a power system. But, it leads to unstable operation when small disturbances are applied. Normally, mechanical part of a synchronous system is intrinsically prone to weakly damped oscillations and the damping of these oscillations must come from other sources, such as damper windings and the machine's controllers. Because power system oscillations have frequencies in the order of a few Hz and of rather small amplitude, hardly any damping is provided by the damper windings, leaving the controllers and the rest of the power system as the main contributors to the damping of the rotor speed oscillations. So in this paper, Power system stabilizer (PSS) is used for providing damping torque. This paper examines the effect of PV sources on small signal stability conditions of conventional power system with Synchronous Generators (SG) along with PSS. Eigen value analysis is conducted after developing a Differential-Algebraic model (DAE) in power balance form and tested on a modified 3 synchronous machine - 9 bus system [10] with PV converters.

Low frequency electromechanical oscillations are inevitable characteristics of power systems and they greatly affect the transmission line transfer capability and power system stability. PSS and FACTS devices can help the damping of power system oscillations. The objective of this paper is to design an advanced PSS and propose a systematic approach for damping controller design for FACTS devices. This paper presents a control scheme, comprehensive analysis and result obtained for the dynamic control of power transmission, damping of oscillations with Unified Power Flow Controller (UPFC) on the basis of theory and computer simulations through MATLAB software. In this paper Unified Power Flow Controller (UPFC) is not designed, but the effect of UPFC on the system under the fault conditions, disturbance, major block outs is being verified.