Analysis of hydromagnetically modulated multiple slips motion of hybrid-nanofluid through a converging/diverging moving channel

The utility of convergent/divergent channel driven flow to improve the effectiveness of heat transport rate in industrial and engineering systems is diverse. This motivates us to disclose hybrid nanofluid flow features through non-parallel walls under hydro-magnetic aspect. The modified Darcian (Darcy–Forchheimer) expression is utilized for formulation. Reflection of improved Darcian form modifies the expression of velocity via square of velocity term. The effects of temperature jump and viscous dissipation are implemented in energy expression. Additionally, the slip flow phenomenon under the stretching/shrinking characteristics is studied. The analysis is carried out under the theory of boundary layer. Significant variables are implemented to acquire the dimensionless mathematical expressions. Dimensionless problem is tackled through a well-known homotopy technique. To observe the upshots of numerous pertinent parameters upon non-dimensional profiles of velocity and temperature, the graphs are plotted for both convergent/divergent channels. The heat transfer rate as well as drag force is also analyzed. In this study, it is concluded that temperature field rises in both divergent/convergent channels for dominant thermal slip parameter. Moreover, inertia parameter effects are seen weaker in converging channel for the velocity profile, while opposite trend is observed for diverging channel.

Chaos generator with high energy potential

An original scheme is proposed for generator of chaos oscillations of the microwave wavelength range. Generator contains nonlinear positive feedback amplifieran and inertial converter of the output signal of a nonlinear amplifier, the signal of which modulates the supply voltage of the active element (transistor). In the case when the value of the inertia parameter of the inertial converter becomes less than 0,06, the generator demonstrated chaotic behavior. An experimental model of a chaotic signal generator based on a powerful transistor 2T982A-2 was created. The generator was created using hybrid microstrip technology on the material FLAN-10 with a thickness of 1 mm. The inertial converter circuit contained a diode performing half-wave conversion of a part of the generator output signal and an RC circuit with a time constant equal to 0,05 of the time one oscillation at the central frequency of the generator. The signal from the output of the inertial converter was applied to the emitter power supply circuit of the transistor. Modulation of the supply voltage led to the fact that the output signal of the generator was a sequence of non-repeating oscillation trains with a random duration and a random initial phase. The frequency band of the generated chaos with an uneven power spectrum of 4 dB occupied a frequency range from 3,1 to 3,3 GHz with an integrated power of 1,2 W. The averaged spectral density of noise oscillations was 6 10-3 W/MHz. Generator efficiency 15%.

Analysis of an Impact of Inertia Parameter in Active Disturbance Rejection Control Structures

This paper is focused on a distributed control of fully actuated manipulators under operating conditions when dynamic couplings between their joints are insignificant. The main research aspect was to examine the influence of the inertia parameter on the tracking quality for control systems based on the active rejection paradigm. The theoretical description and preliminary hypothesis were supported by extensive simulation and experimental results. In particular, it is demonstrated that choosing the inertia parameter according to the real dynamics properties does not guarantee the best performance of the considered control structures.

Inertia Parameter Identification for an Unknown Satellite in Precapture Scenario

The problem of dynamics and control using a space robot to capture a noncooperative satellite is an important issue for on-orbit services. Inertia parameters of the satellite should be identified before capturing such that the robot can design an active controller to finish the capturing task. In this paper, a new identification scheme is proposed for parameter identification of a noncooperative satellite. In this scheme, the space robot is controlled to contact softly and then maintain contact with the noncooperative target firstly, then the variation of momentum of the target during the contact-maintaining phase is calculated using the control force and torque acting on the base of the space robot and the kinematic information of the space robot, and finally, the momentum-conservation-based identification method is used to estimate inertia parameters of the target. To realize soft contact and then maintain contact, a damping contact controller is designed in this paper, in which a mass-damping system is designed to control the contact between the robot and the target. Soft contact and then contact maintenance can be realized by utilizing the buffering characteristics of the mass-damping system. The effectiveness of the proposed identification scheme is verified through numerical simulations at the end of this paper. Simulation results indicate that the proposed scheme can achieve high-precision identification results.

QUANTUM ALGEBRAIC SYMMETRIES IN NUCLEAR AND MOLECULAR PHYSICS

The first realizations of quanttun algebraic symmetries in nuclear and molecular spectra are presented. Rotational spectra of even-even nuclei are described by the quantum algebra SUq(2). The two parameter formula given by the algebra is equivalent to an expan- sion in terms of powers of j(j + 1), similar to the expansion given by the Variable Moment of Inertia (VMI) model. The moment of inertia parameter in the two models, as well as the small parameter of the expansion, are found to have very similar numerical values. The same formalism is found to give very good results for superdeformed nuclear bands, which are closer to the classical SU(2) limit, as well as for rotational bands of diatomic molecules, in which a partial summation of the Dunham expansion for rotation-vibration spectra is achieved. Vibrational spectra of diatomic molecules can be described by the q-deformed anhannonic oscillator, having the symmetry Uq(2)>Oq(2). An alternative de- scription is obtained in terms of the quantum algebra SUq(1,1). In both cases the energy formula obtained is equivalent to an expansion in terms of powers of (v+½) , where ν is the vibrational quantum number, while in the classical ST(1,1) case only the first two powers appear. In all cases the improved description of the empirical data is obtained with q being a phase (and not a real number). Further applications of quantum algebraic symmetries in nuclei and molecules are discussed.