Stress-Strain Behavior of a Smart Magnetostrictive Actuator for a Bone Transport Device

2008 ◽  
Vol 2 (4) ◽  
Author(s):  
Yuehao Luo ◽  
Parsaoran Hutapea
Keyword(s):  
Magnetic Field ◽  
Magnetic Moment ◽  
Longitudinal Direction ◽  
Bone Transport ◽  
Strain Behavior ◽  
Actuation System ◽  
Periosteal Surface ◽  
Magnetostrictive Actuator ◽  
The Magnetic Field ◽  
Transport Device

The ultimate goal of our research is to develop a bone transport device using a magnetostrictive alloy actuation system. The device is designed to be subcutaneously mounted on the periosteal surface of the tibia. The magnetomechanical behavior of Terfenol-D smart magnetostrictive material has been well investigated in the literature when a magnetic field is applied along the longitudinal direction of the Terfenol-D material (perpendicular to the material’s magnetic moment). However, the requirement of our device is to have the magnetic field transversely applied on the Terfenol-D material (along the material’s magnetic moment). Therefore, the objective of this work was to study the magnetomechanical behavior of Terfenol-D under a transversely applied magnetic field. Experimental work was performed and a Terfenol-D material constitutive behavior was investigated.

Magnetostrictive Alloy Actuator for a Bone Transport Device

2008 ◽  
Author(s):  
Parsaoran Hutapea
Keyword(s):  
Magnetic Field ◽  
Experimental Work ◽  
Magnetic Moment ◽  
Longitudinal Direction ◽  
Bone Transport ◽  
Constitutive Behavior ◽  
Actuation System ◽  
Periosteal Surface ◽  
The Magnetic Field ◽  
Transport Device

The ultimate goal of our research is to develop a bone transport device using a magnetostrictive alloy actuation system. The device is designed to be subcutaneously mounted on the periosteal surface of the tibia. The magnetomechanical behavior of Terfenol-D smart magnetostrictive material has been well investigated in the literature when a magnetic field is applied along the longitudinal direction of the Terfenol-D material (perpendicular to the material’s magnetic moment). However, the requirement of our device is to have the magnetic field transversely applied on the Terfenol-D material (along the material’s magnetic moment). Therefore, the objective of this work was to study the magnetomechanical behavior of Terfenol-D under a transversely applied magnetic field. Experimental work was performed and a Terfenol-D material constitutive behavior was investigated.

Design of a Bone Transport Device Using Smart Material Actuators

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Yuehao Luo ◽  
Parsaoran Hutapea
Keyword(s):  
Magnetic Field ◽  
Smart Materials ◽  
Transport Process ◽  
Bone Transport ◽  
Smart Material ◽  
Appropriate Technology ◽  
Proof Of Concept ◽  
Design Concepts ◽  
Periosteal Surface ◽  
Transport Device

The ultimate goal of our research is to develop a wireless, remotely activated, and implantable bone transport (lengthening) device. Our device is subcutaneously mounted on the periosteal surface of the tibia. Smart materials such as temperature-driven nitinol and magnetostrictive terfenol-D were investigated to be used as actuators to provide the required forces for the bone transport process. It was found that an actuator based on terfenol-D with a magnetic field applied transversely (along the material’s magnetic moment) was the more appropriate technology. Design concepts and proof-of-concept work of both smart material technologies are presented.

scholarly journals Neutron anomalous magnetic moment in dense magnetized systems

2018 ◽  
Vol 27 (02) ◽  
pp. 1850011
Author(s):  
Zeinab Rezaei
Keyword(s):  
Magnetic Field ◽  
Equation Of State ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Nuclear Potential ◽  
Order Constraint ◽  
The Magnetic Field

In this work, we calculate the neutron anomalous magnetic moment (AMM) supposing that this value can depend on the density and magnetic field of the system. We employ the lowest-order constraint variation (LOCV) method and [Formula: see text] nuclear potential to calculate the medium dependency of the neutron AMM. It is confirmed that the neutron AMM increases by increasing the density, while it decreases as the magnetic field grows. The energy and equation of state for the system have also been investigated.

SOLAR NEUTRINO FLUX VARIATION AND NEUTRINO MAGNETIC MOMENT

1989 ◽  
Vol 04 (02) ◽  
pp. 111-114 ◽  
Author(s):  
PROBHAS RAYCHAUDHURI
Keyword(s):  
Magnetic Field ◽  
Sunspot Number ◽  
Magnetic Moment ◽  
Solar Neutrino ◽  
Convection Zone ◽  
Neutrino Flux ◽  
Flux Variation ◽  
Neutrino Magnetic Moment ◽  
Solar Neutrino Flux ◽  
The Magnetic Field

It is shown that neutrino flip through the magnetic field of the convection zone is not responsible for the anticorrelation between the solar neutrino flux and the sunspot number.

scholarly journals Полностью оптический магнитометрический датчик для задач магнитоэнцефалографии и томографии сверхслабого поля

2020 ◽  
Vol 46 (17) ◽  
pp. 43
Author(s):  
А.К. Вершовский ◽  
А.С. Пазгалев ◽  
М.В. Петренко
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Shot Noise ◽  
Magnetic Moment ◽  
Resonance Line ◽  
Optical Pumping ◽  
Resonance Excitation ◽  
A Cell ◽  
Resonance Line Width ◽  
The Magnetic Field

A version of the scheme of an atomic cesium vapour magnetometric sensor using magnetic resonance excitation by modulated radiation transverse to the magnetic field of hyperfine optical pumping is proposed and experimentally studied. It is shown that when using a cell with a volume of 0.125 cm3, the variational sensitivity of the sensor, estimated from the ratio of the steepness of the signal at the center of the magnetic resonance to the shot noise of the detecting radiation, reaches a level of less than 10 fT/Hz1/2 in the frequency band determined by the magnetic resonance line width (of the order of 800 Hz). The sensor, which does not use and does not emit resonant radio-frequency fields, is designed to operate in magnetoencephalographic complexes. Possible ways to increase the frequency response of the circuit for detecting relatively fast (~ 4.2 kHz in a field of 0.1 mT) proton magnetic moment precession signals in promising ultralow field tomography schemes are considered.

scholarly journals Stokesian dynamics simulations of a magnetotactic bacterium

2021 ◽  
Vol 44 (3) ◽  
Author(s):  
Sarah Mohammadinejad ◽  
Damien Faivre ◽  
Stefan Klumpp
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Cell Body ◽  
Magnetic Moment ◽  
Magnetotactic Bacteria ◽  
Swimming Velocity ◽  
Stokesian Dynamics ◽  
Inclination Angles ◽  
Dynamics Simulations ◽  
The Magnetic Field

AbstractThe swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically steered swimming of magnetotactic bacteria. We use Stokesian dynamics simulations to study the swimming of single-flagellated magnetotactic bacteria (MTB) in an external magnetic field. Our model MTB consists of a spherical cell body equipped with a magnetic dipole moment and a helical flagellum rotated by a rotary motor. The elasticity of the flagellum as well as magnetic and hydrodynamic interactions is taken into account in this model. We characterized how the swimming velocity is dependent on parameters of the model. We then studied the U-turn motion after a field reversal and found two regimes for weak and strong fields and, correspondingly, two characteristic time scales. In the two regimes, the U-turn time is dominated by the turning of the cell body and its magnetic moment or the turning of the flagellum, respectively. In the regime for weak fields, where turning is dominated by the magnetic relaxation, the U-turn time is approximately in agreement with a theoretical model based on torque balance. In the strong-field regime, strong deformations of the flagellum are observed. We further simulated the swimming of a bacterium with a magnetic moment that is inclined relative to the flagellar axis. This scenario leads to intriguing double helical trajectories that we characterize as functions of the magnetic moment inclination and the magnetic field. For small inclination angles ($$\lesssim {20^{\circ }}$$≲20∘) and typical field strengths, the inclination of the magnetic moment has only a minor effect on the swimming of MTB in an external magnetic field. Large inclination angles result in a strong reduction in the velocity in direction of the magnetic field, consistent with recent observations that bacteria with large inclination angles use a different propulsion mechanism.Graphic abstract

Transport Coefficients and Orientational Distributions of a Dilute Colloidal Dispersion Composed of Hematite Particles: Analysis for an Applied Magnetic Field Parallel to the Angular Velocity Vector of Simple Shear Flow

2006 ◽  
Author(s):  
Ryo Hayasaka ◽  
Akira Satoh ◽  
Tamotsu Majima
Keyword(s):  
Magnetic Field ◽  
Shear Flow ◽  
Magnetic Moment ◽  
Flow Direction ◽  
Transport Coefficients ◽  
Colloidal Dispersion ◽  
Field Direction ◽  
Simple Shear Flow ◽  
Magnetic Field Direction ◽  
The Magnetic Field

We have studied the influences of the magnetic field, shear rate, and random forces on transport coefficients such as viscosity and diffusion coefficient, and also on the orientational distributions of hematite particles composed of a dilute colloidal dispersion. Hematite particles are modeled as spheroids with a magnetic moment normal to the particle axis. In the present analysis, these particles are assumed to conduct the rotational Brownian motion in a simple shear flow as well as an external magnetic field. The basic equation of the orientational distribution function has been derived from the balance of the torques and solved by the numerical analysis method. The results obtained here are summarized as follows. With increasing the magnetic field, since the magnetic moment is strongly restricted to the magnetic field direction, the motion of the particle is forced to rotate in directions normal to the shear flow direction. In the case of a strong magnetic field and a smaller shear rate, the rodlike particles can freely rotate in the xy-plane with the magnetic moment remaining pointing to the magnetic field direction. On the other hand, for a strong shear flow, the particle has a tendency to incline in the flow direction with the magnetic moment pointing to the magnetic field direction. Additionaly, the diffusion coefficient gives rise to smaller values than expected, since the rodlike particle sediments with the particle inclining toward directions normal to the moment direction.

Influences of Magnetic Particle-Particle Interactions on Orientational Distributions and Rheological Properties of a Semi-Dense Colloidal Dispersion Composed of Rod-Like Hematite Particles: Analysis by Means of Mean Field Approximation for an External Magnetic Field Parallel to the Angular Velocity Vector of a Simple Shear Flow

2007 ◽  
Author(s):  
Ryo Hayasaka ◽  
Masayuki Aoshima ◽  
Toshinori Suzuki ◽  
Akira Satoh
Keyword(s):  
Magnetic Field ◽  
Magnetic Moment ◽  
Mean Field ◽  
Field Approximation ◽  
Field Direction ◽  
Magnetic Interactions ◽  
Mean Field Approximation ◽  
Magnetic Field Direction ◽  
Orientational Distribution ◽  
The Magnetic Field

We have investigated mainly the influences of magnetic particle-particle interactions on orientational distributions and viscosity of a semi-dense dispersion, which is composed of rod-like particles with a magnetic moment magnetized normal to the particle axis. In addition, the influences of the magnetic field strength, shear rate, and random forces on the orientational distribution and rheological properties have been clarified. The mean field approximation has been applied to take into account magnetic interactions between rod-like particles. The basic equation of the orientational distribution function has been derived from the balance of torques and solved by the numerical analysis method. The results obtained here are summarized as follows. For a strong magnetic field, the rotational motion of the rod-like particle is restricted in a plane normal to the shearing plane because the magnetic moment of the particle is restricted in the magnetic field direction. Under circumstances of a very strong magnetic interaction between particles, the magnetic moment is strongly restricted in the magnetic field direction, so that the particle has a tendency to incline in the flow direction with the magnetic moment pointing to the magnetic field direction. For a strong shear flow, a directional characteristic of rod-like particles is enhanced, and this leads to a more significant one-peak-type distribution of the orientational distribution function. Magnetic interactions between particles do not contribute to the viscosity because the mean-field vector has only a component along the magnetic field direction.

Quasi-2D Monte Carlo Simulations of a Colloidal Dispersion Composed of Magnetic Plate-Like Particles With Magnetic Moment Normal to the Particle Axis

2008 ◽  
Author(s):  
Akira Satoh ◽  
Yasuhiro Sakuda
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Field Strength ◽  
Monte Carlo Simulations ◽  
Magnetic Field Strength ◽  
Magnetic Moment ◽  
Colloidal Dispersion ◽  
Magnetic Interactions ◽  
The Magnetic Field ◽  
Aggregation Phenomena

We have investigated aggregation phenomena of a colloidal dispersion composed of magnetic plate-like particles by means of Monte Carlo simulations. Such plate-like particles have been modeled as disk-like particles which have a magnetic moment normal to the particle axis at the particle center, with the section shape of a spherocylinder. The main objective of the present study is to clarify the influences of magnetic field strength and magnetic interactions between particles on particle aggregation phenomena. We have concentrated our attention on a quasi-2D system from an application point of view such as development of surface changing technology using such magnetic plate-like particles. A magnetic field was applied along a direction perpendicular to the plane of the monolayer. Internal structures of particle aggregates have been discussed quantitatively in terms of radial distribution and orientational pair correlation functions. The main results obtained here are summarized as follows. For the case of strong magnetic interactions between particles, the particles form long column-like clusters with their magnetic moments alternating in direction between the neighboring particles. These tendencies appear under circumstances of a weak applied magnetic field. However, as the magnetic field strength increases, the particles incline toward the magnetic field direction, so that the particles do not form such clusters.

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