Subjects -> ASTRONOMY (Total: 94 journals)
 Showing 1 - 46 of 46 Journals sorted alphabetically Advances in Astronomy       (Followers: 49) Annual Review of Astronomy and Astrophysics       (Followers: 50) Annual Review of Earth and Planetary Sciences       (Followers: 67) Artificial Satellites       (Followers: 21) Astrobiology       (Followers: 11) Astronomical & Astrophysical Transactions: The Journal of the Eurasian Astronomical Society       (Followers: 7) Astronomical Review       (Followers: 5) Astronomische Nachrichten       (Followers: 4) Astronomy & Geophysics       (Followers: 49) Astronomy and Astrophysics       (Followers: 67) Astronomy and Computing       (Followers: 6) Astronomy Letters       (Followers: 22) Astronomy Reports       (Followers: 22) Astronomy Studies Development       (Followers: 15) Astroparticle Physics       (Followers: 10) Astrophysical Bulletin       (Followers: 4) Astrophysics       (Followers: 35) Astrophysics and Space Science       (Followers: 49) Astrophysics and Space Sciences Transactions (ASTRA)       (Followers: 60) Astropolitics: The International Journal of Space Politics & Policy       (Followers: 13) Celestial Mechanics and Dynamical Astronomy       (Followers: 15) Chinese Astronomy and Astrophysics       (Followers: 25) Colloid Journal       (Followers: 2) Comptes Rendus : Physique       (Followers: 2) Computational Astrophysics and Cosmology       (Followers: 6) Earth and Planetary Science Letters       (Followers: 143) Earth, Moon, and Planets       (Followers: 47) Earth, Planets and Space       (Followers: 77) EAS Publications Series       (Followers: 8) EPL Europhysics Letters       (Followers: 8) Experimental Astronomy       (Followers: 38) Expert Opinion on Astronomy and Astrophysics       (Followers: 8) Extreme Life, Biospeology & Astrobiology - International Journal of the Bioflux Society       (Followers: 4) Few-Body Systems       (Followers: 1) Foundations of Physics       (Followers: 40) Frontiers in Astronomy and Space Sciences       (Followers: 15) Galaxies       (Followers: 6) Globe, The       (Followers: 3) Gravitation and Cosmology       (Followers: 6) Icarus       (Followers: 71) International Journal of Advanced Astronomy       (Followers: 21) International Journal of Astrobiology       (Followers: 4) International Journal of Astronomy       (Followers: 22) International Journal of Astronomy and Astrophysics       (Followers: 36) International Journal of Satellite Communications Policy and Management       (Followers: 15) International Letters of Chemistry, Physics and Astronomy       (Followers: 8) ISRN Astronomy and Astrophysics       (Followers: 14) Journal for the History of Astronomy       (Followers: 20) Journal of Astrobiology & Outreach       (Followers: 5) Journal of Astronomical Instrumentation       (Followers: 3) Journal of Astrophysics       (Followers: 33) Journal of Astrophysics and Astronomy       (Followers: 58) Journal of Atmospheric and Solar-Terrestrial Physics       (Followers: 133) Journal of Geophysical Research : Planets       (Followers: 116) Journal of Geophysical Research : Space Physics       (Followers: 136) Journal of High Energy Astrophysics       (Followers: 25) Kinematics and Physics of Celestial Bodies       (Followers: 11) KronoScope       (Followers: 1) Macalester Journal of Physics and Astronomy       (Followers: 5) Monthly Notices of the Royal Astronomical Society       (Followers: 13) Monthly Notices of the Royal Astronomical Society : Letters       (Followers: 2) Nature Astronomy       (Followers: 14) New Astronomy       (Followers: 26) New Astronomy Reviews       (Followers: 19) Nonlinear Dynamics       (Followers: 19) NRIAG Journal of Astronomy and Geophysics       (Followers: 4) Physics of the Dark Universe       (Followers: 4) Planetary and Space Science       (Followers: 106) Planetary Science       (Followers: 52) Proceedings of the International Astronomical Union       (Followers: 2) Publications of the Astronomical Society of Australia       (Followers: 3) Publications of the Astronomical Society of Japan       (Followers: 4) Research & Reviews : Journal of Space Science & Technology       (Followers: 20) Research in Astronomy and Astrophysics       (Followers: 38) Revista Mexicana de Astronomía y Astrofísica       (Followers: 3) Science China : Physics, Mechanics & Astronomy       (Followers: 4) Science China Physics, Mechanics & Astronomy       (Followers: 4) Solar Physics       (Followers: 29) Solar System Research       (Followers: 15) Space Science International       (Followers: 118) Space Science Reviews       (Followers: 92) Space Weather       (Followers: 27) Transport and Aerospace Engineering       (Followers: 13) Universe       (Followers: 6)
Similar Journals
 Nonlinear DynamicsJournal Prestige (SJR): 1.468 Citation Impact (citeScore): 4Number of Followers: 19      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1573-269X - ISSN (Online) 0924-090X Published by Springer-Verlag  [2469 journals]
• Reproduce the biophysical function of chemical synapse by using a
memristive synapse

Abstract: Abstract Dynamical modeling of nervous systems is of fundamental importance in many scientific fields containing the topics relative to computational neuroscience and biophysics. Many feasible mathematical models have been suggested in the explanation and prediction of some features of neural activities. Considering the special experimental findings and the computational efficiency, it is necessary to find a perfect balance between estimating biophysical functions with complete dynamics and reducing complexity when a tractable model is built. In this paper, a chemical synaptic model is reproduced by using a memristive synapse because it not only remains synaptic characteristic but also exhibits a pinched hysteresis loop and active feature locally. That is, a neuron activated by chemical synapse can produce similar firing modes as the neuron coupled by a memristive synapse, and both the chemical synapse and memristive synapse have similar field effect and biophysical properties. By calculating the one-parameter and two-parameter bifurcation as well as the Lyapunov exponent spectrum, it is confirmed that a neuron can be excited by the chemical synapse or the memristive synapse for generating chaotic firing patterns. Oscillation of the circuit composed of neuron and functional synapse is analyzed, suggesting that there exists a relation between the local activity and the edge of chaos via Hopf bifurcation. A modular circuit is designed to construct large-scale neural network. These results in this paper provide new evidences for application of memristive components and guide us to know the biophysical function of chemical synapse from physical viewpoint, in which the chemical synapse could be a kind of memristive synapse because of the same biophysical function.
PubDate: 2022-05-21

• Study on safety characteristics of the spur gear pair considering
time-varying backlash in the established multi-level safety domains

Abstract: Abstract Multi-state meshing characteristics induced by backlash and contact ratio in the gear pair are an unsolved puzzle about its relationship to safety characteristics of the gear transmission system. A nonlinear dynamics model of spur gear pair considering time-varying backlash, multi-state meshing, contact ratio and other time-varying parameters is improved. The time-varying backlash comprehensively determined by static backlash, tooth elastic deformation, thermal deformation and oil film thickness is calculated to identify the multi-state meshing of the system. The safety characteristics of the system are classified into nine safety levels according to the influence of meshing states on operation stability. Nine safety domains corresponding to the safety levels are established, respectively. An algorithm is proposed to calculate the safe basin of the gear transmission system in established safety domains. The evolution of safety characteristics in established safety domains is investigated from a local and global perspective by safe basin, nonlinear analysis methods, bifurcation and safety dendrograms and statistical methods. The results show that the value of backlash is affected by meshing states and working conditions of the system. Time-varying backlash is important in identifying multi-state meshing and establishing multi-level safety domains. The safety levels of system responses can be judged by established multi-level safety domains, and the safety characteristics of the system are affected by system parameters, motions and bifurcations. It provides a theoretical basis for the prediction of meshing states and the design of system parameters.
PubDate: 2022-05-21

• Passive decomposition and gradient control of fractional-order nonlinear
systems

Abstract: Abstract Vector field decomposition is essential in physics and engineering in order to analyze several dynamical systems that appear in these areas. This paper proposes some novel stabilization methods, where the controller is based on the gradient of the smooth vector flow of a nonlinear fractional-order system. The gradient control is obtained from the Presnov decomposition of a continuously differentiable vector flow. Thus, under some weak conditions, it is possible to achieve Mittag–Leffler stability for some classes of autonomous and non-autonomous nonlinear systems by using some straightforward derivations. Numerical studies based on simulation are presented to show the feasibility of the proposed schemes.
PubDate: 2022-05-21

• N-fold generalized Darboux transformation and breather–rogue waves on
the constant/periodic background for a generalized mixed nonlinear
Schrödinger equation

Abstract: Abstract In this paper, a generalized mixed nonlinear Schrödinger equation, which arises in several physical applications including fluid mechanics (for the weakly nonlinear dispersive water waves), quantum field theory and nonlinear optics, is investigated. An N-fold generalized Darboux transformation (GDT) is constructed, where N is a positive integer. Based on that N-fold GDT, we derive the higher-order rational soliton solutions with the non-vanishing background. Semirational solutions on the constant/periodic background, which are composed of the mth-order rogue wave, the $$(k-m-r)$$ th-order so-called nondegenerate breather and the rth-order so-called degenerate breather, are constructed, where $$k=2,3,\ldots ,N$$ , $$m=1,2,\ldots ,k-1$$ and $$r=0,2,3,\ldots$$ . Breathers on the dark/bright soliton or periodic wave background are presented. Based on the semirational solutions, breather–rogue waves on the constant/periodic background are discussed analytically and graphically. Classification conditions for different types of the breather–rogue waves on the constant/periodic background are given. Triangular structure of the higher-order rogue wave on the periodic background is studied and presented.
PubDate: 2022-05-20

• Nonlinear vibration isolation via an innovative active bionic variable

Abstract: Abstract During the process of spacecraft launch, the extreme vibration environment is the major influence factor that induces the failure of the mission. Inspired by the smooth motions of ostrich racing, an innovative active bionic variable stiffness device is proposed and installed on the traditional payload adapter fitting (PAF) of the rocket, which constitutes a new type of active bionic variable stiffness adapter (ABVSA). It is used as a novel vibration isolation equipment to improve the extreme vibration environment. Moreover, the bionic part is the main component of the ABVSA, which is controlled using the proportional–integral–derivative (PID) active controller. To explore the benefits of ABVSA, the theoretical model of the spacecraft–ABVSA system has been derived in the frame of the Lagrange principle. Furthermore, the nonlinear output frequency response functions (NOFRFs) approach is imported to solve the periodic problems of the system. Then, the numerical results were obtained to validate the effectiveness of ABVSA. The results indicated that the ABVSA could be recognized as a viable approach for vibration isolation during the spacecraft launching. In addition, the influence of ABVSA parameters was investigated in detail, and several interesting phenomena have been confirmed. Overall, this study can serve as efficient guidance for the optimal design of the PAF in engineering practice.
PubDate: 2022-05-20

• Performance review of locking alleviation methods for continuum ANCF beam
elements

Abstract: Abstract The absolute nodal coordinate formulation (ANCF) is a nonlinear finite element approach proposed for the large deformation dynamics analysis of beam- and plate/shell-type structures. In the ANCF approach, elastic forces can be defined using three-dimensional elasticity-based continuum mechanics. This approach is often straightforward, and it makes it possible to use advanced material models in the ANCF framework. However, it has been pointed out in several studies that continuum ANCF-based elements with a full three-dimensional elasticity description can suffer from locking phenomena. In this study, a comparison between various combinations of locking alleviation techniques and their applicability to different ANCF beam variants is studied using numerical examples. Furthermore, the enhanced deformation gradient (EDG) technique, which has been proposed recently in finite element literature, is demonstrated for high-order ANCF beam elements. Based on the numerical tests, none of the currently available techniques are suitable for all types of ANCF elements. The paper also shows that the efficiency and accuracy of the techniques are case-dependent. For the ANCF beam element involving higher-order terms with respect to trapezoidal mode, however, the EDG-based techniques are preferable to reduce locking phenomena.
PubDate: 2022-05-19

• Nonlinear dynamics of dry friction oscillator subjected to combined
harmonic and random excitations

Abstract: Abstract The dynamics of a nonlinear single degree freedom oscillator on a moving belt subjected to combined harmonic and random excitations is numerically investigated. The dynamics is described by differential equations with discontinuities due to dry friction between the mass and the belt. The discontinuous oscillator is modelled as a Filippov system. Discontinuity induced bifurcations such as the adding sliding bifurcations due to harmonic excitation and stochastic bifurcations like the P and D bifurcations are investigated by numerically integrating the equations of motion using an adaptive time stepping method. A bisection approach is used to accurately determine the discontinuity point, and a Brownian tree approach is used to follow the correct Brownian path. The associated Fokker–Planck (FP) equation is solved by the finite element method. The largest Lyapunov exponent is computed by using the Müller jump matrix and the Wedig algorithm. The effects of the system parameters on the dynamics of the system are investigated.
PubDate: 2022-05-18

• Degeneration of solitons for a (2+1)-dimensional BBMB equation in
nonlinear dispersive media

Abstract: Abstract A (2+1)-dimensional nonlinear evolution equation describing the propagation of bore and small-amplitude long waves in nonlinear dispersive media, namely Benjamin–Bona–Mahony–Burgers (BBMB) equation is seriously investigated via different approaches. We will attain classic N-soliton solutions by taking advantage of Hirota bilinear form and symbolic computation. Meanwhile, Y-type solitons are found out via adding a novel restrictive condition to N-soliton solutions. Applying complexification method to N-soliton solutions, T-breathers ( $$T=1,2,3,\ldots$$ ) are constructed. During the degeneration of breathers, rogue waves will be discovered by taking the parameter limit method. Besides, combining long wave limit approach and the complexification method to N-soliton solutions, M-lump ( $$M=1,2,3,\ldots$$ ) solutions and hybrid solutions composed of soliton, breather and lump can be derived, it means that hybrid solutions could emerge through the partial degeneration of N-soliton process. To detect the dynamical behaviors of these solutions vividly, the corresponding numerical simulations are presented in several figures.
PubDate: 2022-05-18

• Online identification of time-variant structural parameters under unknown
inputs basing on extended Kalman filter

Abstract: Abstract To date, many parameter identification methods have been developed for the purpose of structural health monitoring and vibration control. Among them, the extended Kalman filter series methods are attractive in view of the efficient unbiased estimation in recursive manner. However, most of these methods are performed on the premise that the parameters are time-invariant and/or the loadings are known. To circumvent the aforementioned limitations, an online extended Kalman filter with unknown input approach is proposed in this paper for the identification of time-varying parameters and the unknown excitation. A revised observation equation is obtained with the aid of projection matrix. To capture the changes of structural parameters in real time, an online tracking matrix associated with the time-varying parameters is introduced and determined via an optimization procedure. Then, based on the principle of extended Kalman filter, the recursive solution of structural states including the time-variant parameters can be analytically derived. Finally, using the estimated structural states, the unknown inputs are identified by means of least-squares estimation at the same time step. The effectiveness of the proposed approach is validated via linear and nonlinear numerical examples with the consideration of parameters being varied abruptly.
PubDate: 2022-05-18

• Integrable (3+1)-dimensional Ito equation: variety of lump solutions and
multiple-soliton solutions

Abstract: Abstract In this work, we study an extended integrable (3+1)-dimensional Ito equation, where its complete integrability is justified via Painlevé analysis. The simplified Hirota’s method is used to formally derive multiple-soliton solutions. Moreover, we obtain a general class of lump solutions by using symbolic computation with Maple. Lump solutions are furnished for specific cases of the parameters.
PubDate: 2022-05-18

• Study on impact characteristics of electric powertrain in regenerative
braking process

Abstract: Abstract Electromagnetic torque reversal may lead to gear impact during regenerative braking of electric vehicles. To simulate the dynamic response of gear transmission during impact, an electromechanical non-smooth model is established by combining the permanent magnet synchronous motor model with the gear transmission model. In this model, the coast-side mesh stiffness and impact damping are further coupled based on considering the drive-side mesh stiffness, meshing damping, and electromagnetic characteristics. The theoretical model is validated against an experimental platform. The mechanism of gear impact is revealed through the analysis of the gear contact force. Furthermore, the effects of driving status and internal excitations on the impact characteristics are studied. The results show that the initial braking speed and regenerative braking torque greatly influence the impact times and impact force. The impact times for various backlashes change little. Changing rotor inertia and torsional damping can effectively improve impact characteristics. The research provides theoretical support for dynamic load study and life prediction of the electric powertrain.
PubDate: 2022-05-18

• Correction to: Structural and electrical dynamics of a grating-patterned
triboelectric energy harvester with stick–slip oscillation and magnetic
bistability

PubDate: 2022-05-17

• Bifurcation analysis and $$\pmb {H_{\infty }}$$ H ∞ control of a
stochastic competition model with time delay and harvesting

Abstract: Abstract In this paper, a stochastic competition model with time delay and harvesting is investigated. By means of the stochastic center manifold reduction principle and stochastic averaging method, the model is simplified to a one-dimensional Markov diffusing process. The singular boundary theory and invariant measure are applied in analyzing the stochastic stability and bifurcation. The T-S fuzzy model of the system is constructed, and the $$H_{\infty }$$ state feedback controller is designed to eliminate the instability phenomenon by using a linear matrix inequality approach. Finally, numerical simulations are given to demonstrate our results.
PubDate: 2022-05-17

• Correction to: Dynamic behavior analysis of tethered satellite system
based on Floquet theory

PubDate: 2022-05-16

• Analysis of lumps, single-stripe, breather-wave, and two-wave solutions to
the generalized perturbed-KdV equation by means of Hirota’s bilinear
method

Abstract: Abstract In this paper, we implement the Hirota’s bilinear method to extract diverse wave profiles to the generalized perturbed-KdV equation when the test function approaches are taken into consideration. Several novel solutions such as lump-soliton, lump-periodic, single-stripe soliton, breather waves, and two-wave solutions are obtained to the proposed model. We conduct some graphical analysis including 2D and 3D plots to show the physical structures of the recovery solutions. On the other hand, this work contains a correction of previous published results for a special case of the perturbed KdV. Moreover, we investigate the significance of the nonlinearity, perturbation, and dispersion parameters being acting on the propagation of the perturbed KdV. Finally, our obtained solutions are verified by inserting them into the governing equation.
PubDate: 2022-05-16

• Novel bursting dynamics and the mechanism analysis in a mechanical
oscillator

Abstract: Abstract The complex bursting dynamics of a mechanical oscillator under parametric and external forced excitations are investigated. When the frequencies of the forcing terms are much smaller than the natural frequency of the oscillator, excitations can be expressed as slow-varying variables and the oscillator is regarded as a smooth autonomous system. A new route to bursting dynamics called the pulse-shaped explosion (PSE) is then proposed. PSE is represented by a sharp change in the number of pulse-shaped signals corresponding to the transformation of system parameters. Four PSE-type bursting dynamics are analyzed based on the slow-fast analysis method: bursting dynamics of “supHopf/supHopf” form via “PSE/PSE” hysteresis loop, bursting dynamics of “supHopf/supHopf-PSE/supHopf” form via “PSE/PSE” hysteresis loop, bursting dynamics of “supHopf/supHopf-PSE/PSE” form via “PSE/PSE” hysteresis loop and bursting dynamics of “PSE/PSE-PSE/PSE” form via “PSE/PSE” hysteresis loop. In addition, two non-PSE-type bursting dynamics are also investigated: bursting dynamics of “supHopf/supHopf” form and bursting dynamics of “supHopf/supHopf-supHopf/supHopf” form. Our results strengthen the understanding of the PSE-type bursting oscillations and enrich the possible routes to complex bursting behaviors.
PubDate: 2022-05-16

• Nonlinear vibration analysis of a generally restrained double-beam
structure coupled via an elastic connector of cubic nonlinearity

Abstract: Abstract Double-beam structures are frequently encountered in various engineering applications. Their vibration behavior is attracting more and more research attention. The majority of the existing studies are mainly limited to double-beam structures coupled via linear connectors. Additionally, the rotational boundary restraints of double-beam structures are usually neglected, limiting the dynamic analysis of double-beam structures in engineering applications. To study the potential application of the elastic cubic nonlinearity on double-beam structures, the dynamic analysis model of a generally restrained double-beam structure coupled via a flexible connector of cubic nonlinearity is modeled in this study. The Galerkin truncated method (GTM) is employed to solve the nonlinear governing equations of the double-beam structure. Mode functions of beam structures without any nonlinearity and damping are selected as the trail and weight functions. The Galerkin condition is applied to discretize the nonlinear governing equations. Then, residual equations of the double-beam structure are established and arranged into a matrix form. The Runge–Kutta method is utilized to solve the corresponding matrix. The finite difference method (FDM) is applied to verify the correctness and reliability of the current model. Based on the model established, the influence of the coupling nonlinearity on the dynamic behavior of the double-beam structure is studied and discussed. The research found that the variation of nonlinear stiffness, coupling viscous damping, and coupling position can effectively transform vibration states of the double-beam structure. For the determined boundary conditions and structural parameters, a suitable combination of coupling nonlinear stiffness, coupling position, and coupling viscous damping has a beneficial effect on the vibration suppression of the double-beam structure.
PubDate: 2022-05-16

• Theoretical analysis and verification of particles moving along the
arc-shaped surface in vibration machinery

Abstract: Abstract Vibration machinery with an arc-shaped surface as the main working surface widely exists. The experimental phenomenon shows that the bulk material particles exhibit regular sliding motion and throwing motion along the arc-shaped surface under the alternating load of the exciting system. It is essential to systematically investigate the motion theory of particles considering the interactions between the vibration body and the particles. In this paper, firstly, the interaction mechanism between the vibration body and the particles under different motion states is analyzed, and the particle’s kinematics equation is established based on the nonlinear force analysis of sliding motion and throwing motion. After that, the differential equation of the vibration body movement considering the interaction forces is given. Then, the discrete element method (DEM) is used to verify the feasibility of using a small number of particles to study the whole motion law of particle flow. Meanwhile, the correctness of the mechanical model established in this paper and the numerical solution of the vibration system solved by the Newmark-β method are also verified by DEM. Finally, the particle’s motion state intervals are given, and the Sommerfeld effect’s influence on the system’s motion stability is further discussed. In addition, the effects of the nonlinear force, particle mass, friction coefficient, exciting force, and installation angle on the system’s frequency-domain response, conveying efficiency, and throwing index are discussed emphatically. The theoretical basis and experimental method in designing this kind of mechanical equipment are provided for reference.
PubDate: 2022-05-16

• Diverse excitations of two-component rogue waves for a nonautonomous
coupled partially nonlocal nonlinear Schrödinger model under a parabolic
potential

Abstract: Abstract Vector similar structures for solutions with similar expressions of nonlinear models are paid attention in the previous literature. However, the demand of different localized structures of two components for the same system to describe the practical problems is increasing. We take into account a (2+1)-dimensional nonautonomous coupled partially nonlocal nonlinear Schrödinger model under a parabolic potential and erect a projecting expression reducing this nonautonomous equation into an autonomous one. Uniting these solutions of the autonomous equation into the projecting expression, we demonstrate explicit two-component solutions with different forms, including two-component bright–dark Peregrine-type rogue waves and rogue wave doublets. In order to illustrate special properties of these two-component solutions, we study their diverse excitations, such as excitations of two-component rogue waves and rogue wave doublets to full shape, tail-dragged shape, crest-maintaining shape and nascent shape.
PubDate: 2022-05-15

• Nonlinear aeroelastic analysis of a damped elastica-aerofoil system

Abstract: Abstract This work formulates a comprehensive model of a nonlinear aeroelastic system developed for the analysis of complex aeroelastic phenomena related to structural and aerodynamic nonlinearities. The system is formulated as a two-dimensional cantilevered elastica with a rigid airfoil section firmly attached at its tip undergoing large displacements in the crosswind conditions. The system can demonstrate a wide range of domain specific as well as coupled nonlinear phenomena. The structural model is developed by means of the Rayleigh–Ritz approach, with shape functions discretizing both vertical and horizontal displacements and Lagrangian multipliers enforcing inextensibility. Damping is modeled based on a non-local strain-based mechanism in the Kelvin–Voigt arrangement. The resulting structural model is examined through studying the behavior under a follower load and with a tip-attached tendon under tension to study the shape convergence properties and the alignment of the results with known characteristics in the literature. The ONERA dynamic stall model is used to model the aerodynamics of the problem to accurately capture post-stall behavior at large deformations. The LCO responses of the aeroelastic problem are evaluated through time-marched simulations, and the combined airspeed–damping interactions are studied in this manner.
PubDate: 2022-05-14

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