Numerical Simulation of Free Convection in a Three-Dimensional Enclosure Full of Nanofluid with the Existence a Magnetic Field

Blood glucose automatic regulation achievement depends on the robustness of the used control algorithm. However, some constraints were encountered due to the human glucose-insulin regulatory system’s complexity. It is proposed to tackle such a goal through the development of a robust synergetic control algorithm. An adaptive approach is integrated into this synergetic control scheme to handle disturbances and parameters variations. Multiple meal disturbances often occur daily as well as some other stochastic noises making efficient glucose regulation a tough challenge addressed in this paper via a new synergetic scheme. Simulation results show a robust function during multiple meal disturbances with good noise rejection.

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Global MHD Simulation of the Weak Southward IMF Condition for Different Time Resolutions

Frontiers in Astronomy and Space Sciences ◽

10.3389/fspas.2021.758241 ◽

2021 ◽

Vol 8 ◽

Author(s):

Kyung Sun Park

Keyword(s):

Magnetic Field ◽

Electric Field ◽

Magnetic Reconnection ◽

Three Dimensional ◽

Slow Solar Wind ◽

Polar Cap ◽

Plasma Properties ◽

Simulation Results ◽

Field Lines ◽

The Impact

We performed high-resolution three-dimensional global MHD simulations to determine the impact of weak southward interplanetary magnetic field (IMF) (Bz = −2 nT) and slow solar wind to the Earth’s magnetosphere and ionosphere. We considered two cases of differing, uniform time resolution with the same grid spacing simulation to find any possible differences in the simulation results. The simulation results show that dayside magnetic reconnection and tail reconnection continuously occur even during the weak and steady southward IMF conditions. A plasmoid is generated on closed plasma sheet field lines. Vortices are formed in the inner side of the magnetopause due to the viscous-like interaction, which is strengthened by dayside magnetic reconnection. We estimated the dayside magnetic reconnection which occurred in relation to the electric field at the magnetopause and confirmed that the enhanced electric field is caused by the reconnection and the twisted structure of the electric field is due to the vortex. The simulation results of the magnetic field and the plasma properties show quasi-periodic variations with a period of 9–11 min between the appearances of vortices. Also the peak values of the cross-polar cap potential are both approximately 50 kV, the occurrence time of dayside reconnections are the same, and the polar cap potential patterns are the same in both cases. Thus, there are no significant differences in outcome between the two cases.

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A Neural Network Based Adaptive Tracking Controller for Nonholonomic Wheeled Mobile Robots With Unknown Dynamics

Volume 8: Dynamic Systems and Control, Parts A and B ◽

10.1115/imece2010-40856 ◽

2010 ◽

Author(s):

Omid Mohareri ◽

Rached Dhaouadi

Keyword(s):

Neural Network ◽

Control Algorithm ◽

Wheeled Mobile Robots ◽

Adaptive Capabilities ◽

The Neural Network ◽

Robot Tracking ◽

Control Scheme ◽

Tracking Motion ◽

Backstepping Controller ◽

Simulation Results

This paper presents the design, implementation and comparative analysis of an intelligent neural network based controller used for adaptive trajectory tracking of a wheeled mobile robot with unknown dynamics. In this proposed control scheme, the neural network is used to continuously tune the gains of the kinematic based controller in a backstepping structure. The online learning and adaptive capabilities of the neural network are utilized to achieve a smooth and fast robot tracking motion. The simulation results are used to verify the tracking performance of the proposed control algorithm and to compare it with the conventional backstepping controller.

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Effects on magnetic reconnection of a density asymmetry across the current sheet

Annales Geophysicae ◽

10.5194/angeo-26-2471-2008 ◽

2008 ◽

Vol 26 (8) ◽

pp. 2471-2483 ◽

Cited By ~ 54

Author(s):

K. G. Tanaka ◽

A. Retinò ◽

Y. Asano ◽

M. Fujimoto ◽

I. Shinohara ◽

...

Keyword(s):

Magnetic Field ◽

Electric Field ◽

Magnetic Reconnection ◽

Current Sheet ◽

Three Dimensional ◽

Flow Region ◽

Electron Acceleration ◽

Particle In Cell ◽

Line Structure ◽

Simulation Results

Abstract. The magnetopause (MP) reconnection is characterized by a density asymmetry across the current sheet. The asymmetry is expected to produce characteristic features in the reconnection layer. Here we present a comparison between the Cluster MP crossing reported by Retinò et al. (2006) and virtual observations in two-dimensional particle-in-cell simulation results. The simulation, which includes the density asymmetry but has zero guide field in the initial condition, has reproduced well the observed features as follows: (1) The prominent density dip region is detected at the separatrix region (SR) on the magnetospheric (MSP) side of the MP. (2) The intense electric field normal to the MP is pointing to the center of the MP at the location where the density dip is detected. (3) The ion bulk outflow due to the magnetic reconnection is seen to be biased towards the MSP side. (4) The out-of-plane magnetic field (the Hall magnetic field) has bipolar rather than quadrupolar structure, the latter of which is seen for a density symmetric case. The simulation also showed rich electron dynamics (formation of field-aligned beams) in the proximity of the separatrices, which was not fully resolved in the observations. Stepping beyond the simulation-observation comparison, we have also analyzed the electron acceleration and the field line structure in the simulation results. It is found that the bipolar Hall magnetic field structure is produced by the substantial drift of the reconnected field lines at the MSP SR due to the enhanced normal electric field. The field-aligned electrons at the same MSP SR are identified as the gun smokes of the electron acceleration in the close proximity of the X-line. We have also analyzed the X-line structure obtained in the simulation to find that the density asymmetry leads to a steep density gradient in the in-flow region, which may lead to a non-stationary behavior of the X-line when three-dimensional freedom is taken into account.

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Three-dimensional Hybrid Simulation Results of a Variable Magnetic Helicity Signature at Proton Kinetic Scales

The Astrophysical Journal ◽

10.3847/1538-4357/ac3bbc ◽

2022 ◽

Vol 924 (2) ◽

pp. 41

Author(s):

Bernard J. Vasquez ◽

Sergei A. Markovskii ◽

Charles W. Smith

Keyword(s):

Magnetic Field ◽

Solar Wind ◽

Physical Quantity ◽

Large Scale ◽

Three Dimensional ◽

Turbulent Energy ◽

Magnetic Helicity ◽

Intrinsic Variability ◽

Background Magnetic Field ◽

Simulation Results

Abstract Three-dimensional hybrid kinetic simulations are conducted with particle protons and warm fluid electrons. Alfvénic fluctuations initialized at large scales and with wavevectors that are highly oblique with respect to the background magnetic field evolve into a turbulent energy cascade that dissipates at proton kinetic scales. Accompanying the proton scales is a spectral magnetic helicity signature with a peak in magnitude. A series of simulation runs are made with different large-scale cross helicity and different initial fluctuation phases and wavevector configurations. From the simulations a so-called total magnetic helicity peak is evaluated by summing contributions at a wavenumber perpendicular to the background magnetic field. The total is then compared with the reduced magnetic helicity calculated along spacecraft-like trajectories through the simulation box. The reduced combines the helicity from different perpendicular wavenumbers and depends on the sampling direction. The total is then the better physical quantity to characterize the turbulence. On average the ratio of reduced to total is 0.45. The total magnetic helicity and the reduced magnetic helicity show intrinsic variability based on initial fluctuation conditions. This variability can contribute to the scatter found in the observed distribution of solar wind reduced magnetic helicity as a function of cross helicity.

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Position Synchronization of the Biaxial System with a PID Neural Networks Control

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.462-463.766 ◽

2013 ◽

Vol 462-463 ◽

pp. 766-770 ◽

Cited By ~ 1

Author(s):

Wang Yong He ◽

Cong Qiu ◽

Jia He

Keyword(s):

Neural Networks ◽

Control Algorithm ◽

Learning Algorithm ◽

Cross Coupling ◽

Synchronization Error ◽

Control Value ◽

Control Scheme ◽

Simulation Results ◽

The Stability

A new control algorithm based on incorporating proportion integration differentiation (PID) neural networks into cross-coupling technology is developed for position synchronization of biaxial system. The PID neural networks controller is be used to adjust control value injecting two velocity loops of the biaxial system.The learning algorithm of PID neural networks is demonstrate in theory. It is tested by simulation that the proposed control scheme can guarantee the stability and the effectiveness of the biaxial control system.The simulation results show that synchronization error is reduced to 35um from 56um.

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Three-Dimensional Fuzzy Controller and its Optimizing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.562-564.1712 ◽

2012 ◽

Vol 562-564 ◽

pp. 1712-1719

Author(s):

Wei Wei Pan ◽

Jia Xin Chen

Keyword(s):

Linear System ◽

Control Algorithm ◽

Fuzzy Controller ◽

Three Dimensional ◽

Good Control ◽

High Order ◽

Control Effect ◽

Practical Applications ◽

Simulation Results ◽

Non Linear System

The design methods of a kind of three-dimensional fuzzy controller and reasoning rules of its control algorithm, and the relevant simplification technology of three-dimensional table have been advanced in this paper. Self-optimized algorithm of the fuzzy controller has also been presented. The simulation results of high-order non-linear system and test of its practical applications have shown its good control effect.

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Developing a Hybrid Three-Dimensional Model of a Plasma Cloud Undergoing Collisionless Expansion into a Rarefied Ionised Magnetized Medium

Herald of the Bauman Moscow State Technical University Series Natural Sciences ◽

10.18698/1812-3368-2021-3-112-132 ◽

2021 ◽

pp. 112-132

Author(s):

A.S. Dikalyuk

Keyword(s):

Magnetic Field ◽

Numerical Simulation ◽

Numerical Scheme ◽

Three Dimensional ◽

System Of Equations ◽

Plasma Cloud ◽

Dimensional Model ◽

Three Dimensional Model ◽

Induction Equation ◽

Simulation Results

The paper presents the results of developing a hybrid three-dimensional model of collisionless interaction in plasma flows. This model considers ions in kinetical terms (simulated as a set of individual particles) and describes electrons in terms of continuum mechanics (simulated as a fluid). We present the system of equations behind the mathematical model and the physical conditions limiting its applicability. The system includes equations describing ion motion in electromagnetic fields, the quasineutrality equation, equations for calculating the total current density, non-radiative Maxwell's equations, and the generalised Ohm's law. We outline a numerical method for solving our hybrid model equations and describe an algorithm for solving the system of equations over time. We focus on the numerical method for solving the induction equation, which takes possible discontinuous solutions into account and preserves the divergence-free condition for the magnetic field. The paper discusses the issues of increasing the spatial approximation accuracy for the numerical scheme used to solve the induction equation. We present numerical simulation results for collisionless expansion of a plasma cloud into a rarefied ionised gas in the presence of an external magnetic field. These results were obtained using our computer code that implements the hybrid model described. The paper demonstrates some numerical properties of the digital simulation developed, specifically, how the order of accuracy for the numerical scheme approximation designed to solve the induction equation affects numerical simulation results

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