scholarly journals Dual Properties of Polyvinyl Alcohol-Based Magnetorheological Plastomer with Different Ratio of DMSO/Water

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7758
Author(s):  
Norhiwani Mohd Hapipi ◽  
Saiful Amri Mazlan ◽  
Ubaidillah Ubaidillah ◽  
Siti Aishah Abdul Aziz ◽  
Seung-Bok Choi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Polyvinyl Alcohol ◽  
Solvent Mixture ◽  
Binary Solvent ◽  
Solvent Ratio ◽  
Sensors And Actuators ◽  
Relative Shear ◽  
The Matrix ◽  
Mr Effect

Polyvinyl alcohol (PVA)-based magnetorheological plastomer (MRP) possesses excellent magnetically dependent mechanical properties such as the magnetorheological effect (MR effect) when exposed to an external magnetic field. PVA-based MRP also shows a shear stiffening (ST) effect, which is very beneficial in fabricating pressure sensor. Thus, it can automatically respond to external stimuli such as shear force without the magnetic field. The dual properties of PVA-based MRP mainly on the ST and MR effect are rarely reported. Therefore, this work empirically investigates the dual properties of this smart material under the influence of different solvent compositions (20:80, 40:60, 60:40, and 80:20) by varying the ratios of binary solvent mixture (dimethyl sulfoxide (DMSO) to water). Upon applying a shear stress with excitation frequencies from 0.01 to 10 Hz, the storage modulus (G′) for PVA-based MRP with DMSO to water ratio of 20:40 increases from 6.62 × 10−5 to 0.035 MPa. This result demonstrates an excellent ST effect with the relative shear stiffening effect (RSTE) up to 52,827%. In addition, both the ST and MR effect show a downward trend with increasing DMSO content to water. Notably, the physical state of hydrogel MRP could be changed with different solvent ratios either in the liquid-like or solid-like state. On the other hand, a transient stepwise experiment showed that the solvent’s composition had a positive effect on the arrangement of CIPs within the matrix as a function of the external magnetic field. Therefore, the solvent ratio (DMSO/water) can influence both ST and MR effects of hydrogel MRP, which need to be emphasized in the fabrication of hydrogel MRP for appropriate applications primarily with soft sensors and actuators for dynamic motion control.

scholarly journals Correlation of composition, aspect ratio and magnetic resistance of multilayer micro- and nanowires of the “ferromagnetic / diamagnetic” type

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 5-13
Author(s):  
V. M. Fedosyuk
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Aspect Ratio ◽  
Aluminum Oxide ◽  
Giant Magnetoresistance ◽  
Pore Diameter ◽  
Ferromagnetic Layer ◽  
Type I ◽  
Magnetic Layers ◽  
The Matrix

 The results of study of the giant magnetoresistance coefficient (GMR) in multilayer micro- and nanowires based on successively alternating ferromagnetic (Co, CoNi and NiFe) and diamagnetic (Cu) layers are presented in the paper. The samples were obtained by electrochemical deposition into the matrix pores. Aluminum oxide was used as matrices. To establish the influence of the aspect ratio, matrices of two types were used: with a pore diameter of 8 µm and 170–200 nm and a variable thickness from 10 to 60 µm. Investigations of the GMR coefficient were carried out by measuring the current-voltage characteristics in external magnetic fields up to 130 mT. When using type I matrices (pore diameter 8 μm), a positive GMR coefficient (an increase in electrical resistivity in an external magnetic field) was noted, while when using type II matrices (pore diameter 170–200 nm), a negative GMR coefficient was established (a decrease in electrical resistance in an external magnetic field). This is due to the enhancement of the interactions of spin-polarized electrons in the magnetic layers through the copper layer through the RKKY exchange with an increase in the aspect ratio. A significant effect of the composition of the ferromagnetic layer (Co, CoNi, and NiFe) on the value  of the GMR coefficient is noted. The maximum value of the negative GMR coefficient (up to –27.5 %) was established for the CoNi-based nanowire system. The use of multilayer micro- and nanowires, electrolytically deposited in a matrix of aluminum oxide with the ability to control the GMR coefficients, opens up perspective use of these objects as sensitive elements (sensors) of a constant magnetic field, as well as devices for storing magnetic information with a vertical principle. 

The Formation Energy of Martensite Nuclei and the Phase Transition Kinetics under the Action of an External Magnetic Field

2021 ◽  
Vol 410 ◽  
pp. 3-8
Author(s):  
Viktor N. Pustovoit ◽  
Yuri V. Dolgachev
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Initial Phase ◽  
Formation Energy ◽  
Martensite Phase ◽  
Nucleation Center ◽  
Austenite Matrix ◽  
Ferromagnetic Order ◽  
The Matrix ◽  
Phase Transition Kinetics

The formation energy of martensite nuclei in the austenite matrix is calculated. Nanoclusters with ferromagnetic order, which exist in austenite above the Curie temperature, reduce the formation energy of a critical martensite nucleation center when exposed to an external magnetic field. The data obtained are explained by the magnetic separation of the initial phase under the action of a magnetic field. A fluctuation increase in nanovolumes with a ferromagnetic order in austenite increases the energy in a atoms group of the matrix phase with a parallel spins arrangement. As a result, the nucleation rate of the martensite phase increases and the martensitic transformation proceeds more completely.

MAGNETORHEOLOGICAL ELASTOMERS BASED ON POLYURETHANE/SI-RUBBER HYBRID

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1114-1120 ◽  
Author(s):  
Y. Hu ◽  
Y. L. Wang ◽  
X. Q. Gong ◽  
X. L. Gong ◽  
X. Z. Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Preparation Condition ◽  
Sem Analysis ◽  
Maximum Increase ◽  
Magnetorheological Elastomers ◽  
Testing Conditions ◽  
Preparation Conditions ◽  
The Matrix ◽  
Mr Effect ◽  
The Relationship

A kind of magnetorheological elastomers based on polyurethane (PU)/silicone rubber ( Si -rubber) hybrid is fabricated without applying magnetic fields. The MR effect is improved by optimizing preparation conditions, in particular by adjusting PU/Si -rubber ratio, and improving compatibility between PU and Si -rubber. The influences of the preparation condition and the relationship between the microstructure and MR effect of this kind of magnetorheological elastomers are discussed in detail. The results show that this kind of MR elastomers has better MR effect than that of MR elastomers based on pure Si -rubber or PU matrix with same testing conditions. SEM analysis indicates that the former forms a peculiar interpenetrating microstructure in the presence of PU in the matrix. The maximum increase in shear modulus of this kind of MR elastomers can be up to 0.5MPa when exposed to a magnetic field of about 0.2T.

Energy Absorption/Dissipation Performances of Magnetic-Sensitive Rubber (MSR) With Hollow Iron Balls

2015 ◽  
Author(s):  
Shengqiang Zhang ◽  
Lingyu Sun ◽  
Dingxin Leng ◽  
Bincheng Huang ◽  
Jun Xu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Energy Absorption ◽  
Strain Energy ◽  
Effective Strain ◽  
Stress Concentrations ◽  
Buffer Material ◽  
The Matrix ◽  
Thin Walled ◽  
Applied External Magnetic Field

A kind of novel smart buffer material, magnetic-sensitive rubber (MSR) with embedded thin-walled iron balls, is provided, and the energy absorption and energy dissipation properties are investigated numerically. Two kinds of representative volume elements (RVEs) of MSR specimens with solid or hollow iron balls are studied, respectively. Under uniaxial compression alone or combined with magnetic field, the relation between effective stress and effective strain and that between strain energy desity and total compression deformation for these two specimens are established, respectively. With the increase of strain, it is demonstrated numerically that the MSRs with hollow iron balls have better energy absorption/dissipation capability than previous MSRs with solid balls. And the applied external magnetic-field increases this capability more. Under compression, the stress concentrations in elastomer matrix around the hollow balls decrease, that could increase the ultimate compression loads before the matrix failures. This is beneficial for us to design lightweight and efficient buffers according to different application cases.

Angular dependence of the magnetoresistance effect in a silicon based p–n junction device

Nanoscale ◽  
2014 ◽  
Vol 6 (8) ◽  
pp. 3978-3983 ◽  
Author(s):  
Tao Wang ◽  
Mingsu Si ◽  
Dezheng Yang ◽  
Zhong Shi ◽  
Fangcong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Space Charge ◽  
Angular Dependence ◽  
Space Charge Region ◽  
Magnetoresistance Effect ◽  
Junction Device ◽  
Mr Effect ◽  
Silicon Based

Anisotropic MR effect is seen in a non-magnetic p–n junction due to the space charge region being modulated by an external magnetic field.

Factorization of the evolution operator for a spin–orbit coupled system in an external magnetic field for an arbitrary L and

1976 ◽  
Vol 54 (23) ◽  
pp. 2295-2305
Author(s):  
R. Bogdanović ◽  
M. A. Whitehead ◽  
M. S. Gopinathan
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Evolution Operator ◽  
Coupled System ◽  
Projection Operators ◽  
Spin Orbit ◽  
Group Representations ◽  
Special Cases ◽  
The Matrix ◽  
Strong External Field

The evolution operator of the spin–orbit coupled system in an external magnetic field is factorized according to the operator equation:[Formula: see text]where HSO is the spin–orbit coupled Hamiltonian and HZ is the Zeeman Hamiltonian. The preceding equation is expressed in matrix form using the theory of the O(4) group representations. For the special case of [Formula: see text], an explicit form of the matrix C(t) is found. The operator corresponding to the matrix C(t) is found in a closed form using the projection operators constructed in the Appendix. Two special cases, corresponding to a weak and a strong external field, are considered, and possible applications of the results obtained are indicated.

Orientation loss of microcrystals of DyBa2Cu3Oy in a polymer composite during curing of the medium under an external magnetic field

CrystEngComm ◽  
2020 ◽  
Vol 22 (34) ◽  
pp. 5606-5612
Author(s):  
Tsunehisa Kimura ◽  
Hayato Kashiwagi ◽  
Fumiko Kimura ◽  
Shigeru Horii ◽  
Kazuki Takeda ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Polymer Composite ◽  
X Ray Diffraction ◽  
Consolidation Process ◽  
X Ray ◽  
The Matrix

The orientation loss of microcrystals during solidifying the matrix in a magnetic field was modeled. In situ X-ray diffraction results obtained for the consolidation process of DyBa2Cu3Oy microcrystal suspension were explained by the model presented.

Study on Epoxy Based Magnetorheological Elastomers

2011 ◽  
Vol 306-307 ◽  
pp. 852-856 ◽  
Author(s):  
Xiang Wang ◽  
He Yi Ge ◽  
Hua Shi Liu
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Iron Content ◽  
Room Temperature ◽  
Magnetorheological Elastomers ◽  
The Matrix ◽  
Mr Effect ◽  
Scanning Electron

To improve the mechanical properties and the MR effect of MRE, we use flexible epoxy as the matrix of MRE. It shows that both the mechanical properties and the MR effect of epoxy based MRE improved. At room temperature the highest absolute modulus increase was 203 MPa when the intensity of magnetic field was 0.2T while the carbonyl iron content was 71.4%. Temperature influenced the MR effect. When at -40°C the maximum storage modulus increased more than 2356 MPa and changed with the temperature. Meanwhile, the morphology of the epoxy based MRE was studied by scanning electron microscopy (SEM).

Magnetorheological Elastomer Silicone-Based Containing Corroded Carbonyl Iron Particles

2018 ◽  
Vol 772 ◽  
pp. 51-55 ◽  
Author(s):  
Nor Azlin Nazira Abd Rahman ◽  
Saiful Amri Mazlan ◽  
Siti Aishah Abdul Aziz ◽  
Nur Azmah Nordin ◽  
Ubaidillah ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Carbonyl Iron ◽  
Dilute Hydrochloric Acid ◽  
Weight Percent ◽  
Iron Particles ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
The Matrix ◽  
Mr Effect ◽  
And Storage

In this study, magnetorheological elastomers (MREs) were synthesized using silicone rubber (SR) as the matrix element interspersed with 70 weight percent of corroded carbonyl iron particles (CIPs). The CIPs were corroded in dilute hydrochloric acid (HCl) for 4 hours. The rheological properties related to MR effect were experimentally examined in the absence and presence of magnetic field at various current using a rheometer. The experimental results depicted the MR effect of the MRE with corroded CIPs decreased one-half, 27% as compared to the non-corroded samples, 58%. The correlation between the purity of CIPs and storage modulus of MR elastomer is examined in this study.

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