scholarly journals Approaching Resonant Absorption of Environmental Xenobiotics Harmonic Oscillation by Linear Structures

2012 ◽  
Vol 4 (4) ◽  
pp. 561-573 ◽  
Author(s):  
Cornelia A. Bulucea ◽  
Marc A. Rosen ◽  
Nikos E. Mastorakis ◽  
Carmen A. Bulucea ◽  
Corina C. Brindusa
Keyword(s):  
Harmonic Oscillation ◽  
Resonant Absorption ◽  
Linear Structures

scholarly journals Approaching Resonant Absorption of Environmental Xenobiotics Harmonic Oscillation by Linear Structures

2011 ◽  
Author(s):  
Marc Rosen ◽  
Cornelia Bulucea ◽  
Corina Brindusa ◽  
Nikos Mastorakis
Keyword(s):  
Harmonic Oscillation ◽  
Resonant Absorption ◽  
Linear Structures

Linear Visco-Resistive Computations of Magnetohydrodynamic Waves: I. The Code and Test Cases

1994 ◽  
Vol 144 ◽  
pp. 503-505
Author(s):  
R. Erdélyi ◽  
M. Goossens ◽  
S. Poedts
Keyword(s):  
Resonant Absorption ◽  
Numerical Code ◽  
Mhd Waves ◽  
Test Cases ◽  
Numerical Accuracy ◽  
Element Discretization ◽  
Flux Tubes ◽  
Magnetohydrodynamic Waves ◽  
Viscosity Coefficients ◽  
Magnetic Flux Tubes

AbstractThe stationary state of resonant absorption of linear, MHD waves in cylindrical magnetic flux tubes is studied in viscous, compressible MHD with a numerical code using finite element discretization. The full viscosity tensor with the five viscosity coefficients as given by Braginskii is included in the analysis. Our computations reproduce the absorption rates obtained by Lou in scalar viscous MHD and Goossens and Poedts in resistive MHD, which guarantee the numerical accuracy of the tensorial viscous MHD code.

Spin Resonance

2018 ◽  
Author(s):  
M. M. Glazov
Keyword(s):  
Magnetic Resonance ◽  
Nuclear Spin ◽  
Electromagnetic Waves ◽  
Zeeman Splitting ◽  
Resonant Absorption ◽  
Magnetic Interactions ◽  
Spin Effects ◽  
Crystalline Environment ◽  
Spin Resonance ◽  
Optically Detected

This chapter is devoted to one of key phenomena in the field of spin physics, namely, resonant absorption of electromagnetic waves under conditions where the Zeeman splitting of spin levels in magnetic field is equal to photon energy. This method is particularly important for identification of nuclear spin effects, because resonance spectra provide fingerprints of different involved spin species and make it possible to distinguish different nuclear isotopes. As discussed in this chapter the nuclear magnetic resonance provides also an access to local magnetic fields acting on nuclear spins. These fields are caused by the magnetic interactions between the nuclei and by the quadrupole splittings of nuclear spin states in anisotropic crystalline environment. Manifestations of spin resonance in optical responses of semiconductors–that is, optically detected magnetic resonance–are discussed.

scholarly journals A Bio-Inspired Compliance Planning and Implementation Method for Hydraulically Actuated Quadruped Robots with Consideration of Ground Stiffness

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2838
Author(s):  
Xiaoxing Zhang ◽  
Haoyuan Yi ◽  
Junjun Liu ◽  
Qi Li ◽  
Xin Luo
Keyword(s):  
Harmonic Oscillation ◽  
Ground Surface ◽  
Legged Locomotion ◽  
Soft Ground ◽  
Quadruped Robots ◽  
In Series ◽  
Reaction Forces ◽  
Implementation Method ◽  
The Stability ◽  
Natural Dynamics

There has been a rising interest in compliant legged locomotion to improve the adaptability and energy efficiency of robots. However, few approaches can be generalized to soft ground due to the lack of consideration of the ground surface. When a robot locomotes on soft ground, the elastic robot legs and compressible ground surface are connected in series. The combined compliance of the leg and surface determines the natural dynamics of the whole system and affects the stability and efficiency of the robot. This paper proposes a bio-inspired leg compliance planning and implementation method with consideration of the ground surface. The ground stiffness is estimated based on analysis of ground reaction forces in the frequency domain, and the leg compliance is actively regulated during locomotion, adapting them to achieve harmonic oscillation. The leg compliance is planned on the condition of resonant movement which agrees with natural dynamics and facilitates rhythmicity and efficiency. The proposed method has been implemented on a hydraulic quadruped robot. The simulations and experimental results verified the effectiveness of our method.

scholarly journals Resonant Instability of Kink Oscillations in Magnetic Flux Tubes with Siphon Flow

Solar Physics ◽  
2021 ◽  
Vol 296 (6) ◽  
Author(s):  
Michael S. Ruderman ◽  
Nikolai S. Petrukhin
Keyword(s):  
Flow Velocity ◽  
Resonant Absorption ◽  
Tube Axis ◽  
Magnetic Tube ◽  
Transitional Layer ◽  
Threshold Velocity ◽  
Flux Tubes ◽  
Resonant Instability ◽  
Constant Magnitude ◽  
Magnetic Flux Tubes

AbstractWe study kink oscillations of a straight magnetic tube in the presence of siphon flows. The tube consists of a core and a transitional or boundary layer. The flow velocity is parallel to the tube axis, has constant magnitude, and confined in the tube core. The plasma density is constant in the tube core and it monotonically decreases in the transitional layer to its value in the surrounding plasma. We use the expression for the decrement/increment previously obtained by Ruderman and Petrukhin (Astron. Astrophys.631, A31, 2019) to study the damping and resonant instability of kink oscillations. We show that, depending on the magnitude of siphon-velocity, resonant absorption can cause either the damping of kink oscillations or their enhancement. There are two threshold velocities: When the flow velocity is below the first threshold velocity, kink oscillations damp. When the flow velocity is above the second threshold velocity, the kink oscillation amplitudes grow. Finally, when the flow velocity is between the two threshold velocities, the oscillation amplitudes do not change. We apply the theoretical result to kink oscillations of prominence threads. We show that, for particular values of thread parameters, resonant instability can excite these kink oscillations.

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