Fabrication of a piezoelectric polyvinylidene fluoride/carbonyl iron (PVDF/CI) magnetic composite film towards the magnetic field and deformation bi-sensor

2018 ◽  
Vol 165 ◽  
pp. 31-38 ◽  
Author(s):  
Min Sang ◽  
Sheng Wang ◽  
Mei Liu ◽  
Linfeng Bai ◽  
Wanquan Jiang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Composite Film ◽  
Carbonyl Iron ◽  
Polyvinylidene Fluoride ◽  
Magnetic Composite ◽  
The Magnetic Field

scholarly journals Experimental Study of Sidewall Pressure Induced by Ferroparticles in Fluid under a Pulsating Magnetic Field

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 98
Author(s):  
Or Werner ◽  
Asaf Azulay ◽  
Boris Mikhailovich ◽  
Avi Levy
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Polyvinylidene Fluoride ◽  
Particle Interaction ◽  
Cardiac Pacing ◽  
Field Exposure ◽  
Water Chamber ◽  
The Masses ◽  
Fluoride Sensor ◽  
The Magnetic Field

For several decades, magnetic nano- and microparticles have been used in various applications, as they can be attracted and controlled using external magnetic fields. Recently, carbonyl iron microparticles were used in a feasibility study of a new cardiac pacing application. The particles were inserted into a heart, attracted to its sidewall using a pulsating magnetic field, and applied pulsating pressure on its sidewall. The magnitude of the sidewall pressure is a critical parameter for the success and safety of the application, and it was evaluated analytically using a simplified model. In the present study, the behaviour of carbonyl iron microparticles in a water chamber was studied experimentally. Several masses of these particles were attracted to the sidewall of the chamber using an external pulsating magnetic field; the behaviours of the masses of particles, the particle–particle interaction, and the influence of fluid dynamics on them were examined during different periods of pulses. The sidewall pressure during their attraction was measured using an in-house piezoelectric polyvinylidene fluoride sensor. The relations between the measured sidewall pressure and the mass of the particles, their sizes, and the magnetic field exposure time were investigated. The obtained results suggest an asymptotic sidewall pressure value for the specified magnetic field. The measurements of the sidewall pressure are compared with evaluated results from the analytical model, showing that the model over-predicts the sidewall pressure.

Soft Robot Based on Hyperelastic Buckling Controlled by Discontinuous Magnetic Field

2021 ◽  
pp. 1-35
Author(s):  
Yingdong Xu ◽  
Dongze Yan ◽  
Kai Zhang ◽  
Xuequan Li ◽  
Y.F. Xing ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Flexible Electronics ◽  
Nonlinear Deformation ◽  
Numerical Models ◽  
Optical Path ◽  
Magnetic Composite ◽  
Soft Robot ◽  
New Ideas ◽  
Cargo Transportation ◽  
The Magnetic Field

Abstract Most untethered magnetic soft robots are controlled by a continuously applied magnetic field. The accuracy of their motion depends completely on the accuracy of external magnetic field, consequently any slight disturbance may cause a dramatic change. Here, we report a new structure and driven method design to achieve a novel magnetic soft robot, which can achieve accurate and stable locomotion with weakly dependence on the magnetic field. The robot consists of functional magnetic composite materials with one central transportation platform and four crawling arms, whose motion is mainly based on hyperelastic buckling and recovering of the arms. The robot is capable of cargo transportation with multimodal locomotion, such as crawling, climbing and turning with high adaptability to various surfaces. The robot consumes much less driven energy compared to conventional magnetic robots. Moreover, we develop theoretical and numerical models to rationally design the precisely controlled robot. Our study shows applications in terms of transportation functions, such as for optical path adjustments and photographic tasks in complex circumstances. This work also provides new ideas on how to utilize nonlinear deformation more efficiently, one could combine the benefits for both the flexible electronics and actuation applications.

Tuning Active Magnetorheological Elastomers for Damping Applications

2010 ◽  
Vol 636-637 ◽  
pp. 766-771 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Volume Fraction ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Ferromagnetic Component ◽  
Electron And Light Microscopy ◽  
Tan Δ ◽  
Microscopy Techniques ◽  
The Magnetic Field

Magnetorheological elastomers (MREs) were obtained by mixing soft polyurethane and carbonyl-iron particles. The effect of the volume fraction of the ferromagnetic particles on the MREs microstructure and properties, as well as their arrangement in relation to the external magnetic field were investigated. As a ferromagnetic component carbonyl–iron powder, with particle size from 6-9µm, was used. The amount of the carbonyl iron particles was varied from 1.5 to 33.0 %(v/v). The samples were produced with randomly dispersed and aligned carbonyl iron particles. Scanning electron and light microscopy techniques were used for the MRE microstructure observations. The rheological properties (G’, G’’ and tan δ) of the MRE were tested without and with the application of the magnetic field. It was found that the microstructure of MREs, particularly the amount and arrangement of the carbonyl-iron particles, has a significant influence on their rheological and damping properties.

scholarly journals Enhanced Magnetorheological Performance of Carbonyl Iron Suspension Added With Barium Ferrite Nanoparticle

2021 ◽  
Vol 8 ◽  
Author(s):  
Hyo Seon Jang ◽  
Qi Lu ◽  
Hyoung Jin Choi
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Barium Ferrite ◽  
Flow Behavior ◽  
Vibrating Sample Magnetometry ◽  
Mr Fluid ◽  
Mr Fluids ◽  
Ferrite Nanoparticle ◽  
The Magnetic Field ◽  
Mr Characteristics

Hard-magnetic barium ferrite (BF) nanoparticles with a hexagonal plate-like structure were used as an additive to a carbonyl iron (CI) microparticle-based magnetorheological (MR) fluid. The morphology of the pristine CI and CI/BF mixture particles was examined by scanning electron microscopy. The saturation magnetization and coercivity values of each particle were measured in the powder state by vibrating sample magnetometry. The MR characteristics of the CI/BF MR fluid measured using a rotation rheometer under a range of magnetic field strengths were compared with those of the CI-based MR fluid. The flow behavior of both MR fluids was fitted using a Herschel–Bulkley model, and their stress relaxation phenomenon was examined using the Schwarzl equation. The MR fluid with the BF additive showed higher dynamic and elastic yield stresses than the MR fluid without the BF additive as the magnetic field strength increased. Furthermore, the BF nanoparticles embedded in the space between the CI microparticles improved the dispersion stability and the MR performance of the MR fluid.

Effect of the Processing Conditions on the Mechanical Properties of Urethane Magnetorheological Elastomers

2008 ◽  
Vol 587-588 ◽  
pp. 630-634 ◽  
Author(s):  
Anna Boczkowska ◽  
Stefan F. Awietjan
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Carbonyl Iron ◽  
Magnetic Field Effect ◽  
Displacement Sensor ◽  
Compression Tests ◽  
Iron Particles ◽  
Magnetorheological Elastomers ◽  
Chemical Company ◽  
The Magnetic Field

The aim of the study was to develop an innovative processing method of magnetorheological elastomers (MRE). This method comprises optimization of the MRE structure in the context of their performance in the magnetic field. The influence of the amount of ferromagnetic particles and their arrangement in relation to the external magnetic field was investigated. Urethane magnetorheological elastomers were manufactured using polyurethane gels, supplied by Dow Chemical Company. As the ferromagnetic carbonyl–iron powder with particles size from 6-9)m produced by Fluka was used. The amount of the carbonyl iron particles was varied from 1.5 to 33.0 vol. %. Magnetic field strengths used during the fabrication of MRE were 0.1 and 0.3 T. The samples with particle chains aligned or slopped at 45 degree to the long sample axis were produced. To evaluate the external magnetic field effect on the magnetorheological properties a deflection in the magnetic field was measured. Samples were placed parallel to the magnetic field lines and deflected prior to the application of a magnetic field. After the application of the magnetic field the sample tended to straighten which was measured by displacement sensor. Magnetic field in a range of 0-0.9 T has been applied. Also the compression tests were carried out without and within external magnetic field with the strength of 0.3 T. The experiment showed that application of the magnetic field increases stiffness of the material. The amount of iron particles and their arrangement have influence on the stress-strain curves course.

scholarly journals Laser reprogramming magnetic anisotropy in soft composites for reconfigurable 3D shaping

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Heng Deng ◽  
Kianoosh Sattari ◽  
Yunchao Xie ◽  
Ping Liao ◽  
Zheng Yan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Change ◽  
Composite Film ◽  
Magnetic Particles ◽  
Three Dimensional ◽  
Soft Materials ◽  
Magnetic Composite ◽  
Laser Writing ◽  
Soft Robots ◽  
Direct Laser

AbstractResponsive soft materials capable of exhibiting various three-dimensional (3D) shapes under the same stimulus are desirable for promising applications including adaptive and reconfigurable soft robots. Here, we report a laser rewritable magnetic composite film, whose responsive shape-morphing behaviors induced by a magnetic field can be digitally and repeatedly reprogrammed by a facile method of direct laser writing. The composite film is made from an elastomer and magnetic particles encapsulated by a phase change polymer. Once the phase change polymer is temporarily melted by transient laser heating, the orientation of the magnetic particles can be re-aligned upon change of a programming magnetic field. By the digital laser writing on selective areas, magnetic anisotropies can be encoded in the composite film and then reprogrammed by repeating the same procedure, thus leading to multimodal 3D shaping under the same actuation magnetic field. Furthermore, we demonstrated their functional applications in assembling multistate 3D structures driven by the magnetic force-induced buckling, fabricating multistate electrical switches for electronics, and constructing reconfigurable magnetic soft robots with locomotion modes of peristalsis, crawling, and rolling.

Observing the galactic magnetic field

1967 ◽  
Vol 31 ◽  
pp. 375-380
Author(s):  
H. C. van de Hulst
Keyword(s):  
Magnetic Field ◽  
Fair Agreement ◽  
Solar Neighbourhood ◽  
Galactic Magnetic Field ◽  
The Magnetic Field

Various methods of observing the galactic magnetic field are reviewed, and their results summarized. There is fair agreement about the direction of the magnetic field in the solar neighbourhood:l= 50° to 80°; the strength of the field in the disk is of the order of 10-5gauss.

Evolution of Large-Scale Coronal Structures

1994 ◽  
Vol 144 ◽  
pp. 29-33
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Field Line ◽  
Large Scale ◽  
Coronal Magnetic Field ◽  
Source Surface ◽  
Solar Cycles ◽  
Characteristic Relationship ◽  
The Magnetic Field ◽  
Coronal Structures

AbstractThe large-scale coronal structures observed during the sporadically visible solar eclipses were compared with the numerically extrapolated field-line structures of coronal magnetic field. A characteristic relationship between the observed structures of coronal plasma and the magnetic field line configurations was determined. The long-term evolution of large scale coronal structures inferred from photospheric magnetic observations in the course of 11- and 22-year solar cycles is described.Some known parameters, such as the source surface radius, or coronal rotation rate are discussed and actually interpreted. A relation between the large-scale photospheric magnetic field evolution and the coronal structure rearrangement is demonstrated.

Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

2000 ◽  
Vol 179 ◽  
pp. 263-264
Author(s):  
K. Sundara Raman ◽  
K. B. Ramesh ◽  
R. Selvendran ◽  
P. S. M. Aleem ◽  
K. M. Hiremath
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Magnetic Flux ◽  
Ultra Violet ◽  
Active Regions ◽  
Morphological Properties ◽  
Energy Storage And Conversion ◽  
The Sun ◽  
X Rays ◽  
The Magnetic Field

Extended AbstractWe have examined the morphological properties of a sigmoid associated with an SXR (soft X-ray) flare. The sigmoid is cospatial with the EUV (extreme ultra violet) images and in the optical part lies along an S-shaped Hαfilament. The photoheliogram shows flux emergence within an existingδtype sunspot which has caused the rotation of the umbrae giving rise to the sigmoidal brightening.It is now widely accepted that flares derive their energy from the magnetic fields of the active regions and coronal levels are considered to be the flare sites. But still a satisfactory understanding of the flare processes has not been achieved because of the difficulties encountered to predict and estimate the probability of flare eruptions. The convection flows and vortices below the photosphere transport and concentrate magnetic field, which subsequently appear as active regions in the photosphere (Rust & Kumar 1994 and the references therein). Successive emergence of magnetic flux, twist the field, creating flare productive magnetic shear and has been studied by many authors (Sundara Ramanet al.1998 and the references therein). Hence, it is considered that the flare is powered by the energy stored in the twisted magnetic flux tubes (Kurokawa 1996 and the references therein). Rust & Kumar (1996) named the S-shaped bright coronal loops that appear in soft X-rays as ‘Sigmoids’ and concluded that this S-shaped distortion is due to the twist developed in the magnetic field lines. These transient sigmoidal features tell a great deal about unstable coronal magnetic fields, as these regions are more likely to be eruptive (Canfieldet al.1999). As the magnetic fields of the active regions are deep rooted in the Sun, the twist developed in the subphotospheric flux tube penetrates the photosphere and extends in to the corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the Sun, to pin down the energy storage and conversion process that trigger the flare phenomena.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

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