scholarly journals Microfibrillated Cellulose Suspension and Its Electrorheology

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2119 ◽  
Author(s):  
Kisuk Choi ◽  
Jae Do Nam ◽  
Seung Hyuk Kwon ◽  
Hyoung Jin Choi ◽  
Md Sakinul Islam ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Chemical Structure ◽  
Microfibrillated Cellulose ◽  
Shear Stresses ◽  
Power Law Model ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Alkaline Delignification ◽  
Er Fluid

Microfibrillated cellulose (MFC) particles were synthesized by a low-pressure alkaline delignification process, and their shape and chemical structure were investigated by SEM and Fourier transformation infrared spectroscopy, respectively. As a novel electrorheological (ER) material, the MFC particulate sample was suspended in insulating oil to fabricate an ER fluid. Its rheological properties—steady shear stress, shear viscosity, yield stress, and dynamic moduli—under electric field strength were characterized by a rotational rheometer. The MFC-based ER fluid demonstrated typical ER characteristics, in which the shear stresses followed the Cho–Choi–Jhon model well under electric field strength. In addition, the solid-like behavior of the ER fluid was investigated with the Schwarzl equation. The elevated value of both dynamic and elastic yield stresses at applied electric field strengths was well described using a power law model (~E1.5). The reversible and quick response of the ER fluid was also illustrated through the on–off test.

THE FREQUENCY DEPENDENCE AND NON-LINEAR DIELECTRIC PROPERTY OF ER FLUID

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3073-3080 ◽  
Author(s):  
KUNQUAN LU ◽  
WEIJIA WEN ◽  
CHENXI LI
Keyword(s):  
Dielectric Property ◽  
Field Strength ◽  
Electric Field ◽  
Frequency Dependence ◽  
Threshold Value ◽  
Shear Stresses ◽  
Linear Behavior ◽  
Non Linear ◽  
Er Fluids ◽  
Er Fluid

The frequency dependence of the shear stress in ac field and the non-linear dielectric property of ER fluid have been studied. We find that the shear stresses of some water-free ER fluids increase monotonously with the frequency and tend to reach saturated values at high frequency. The measurements on KNbO 3/silicone ER fluid show that the shear stresses under 103 Hz frequency a.c. field are several times or even an order larger than that under d.c. field for the same field strength. The studies of non-linear dielectric properties of ER fluids show that the permittivity of ER fluid increases linearly with increasing field strength when the electric field exceeds a threshold value E 1 and tends to a saturated constant beyond a high field strength E 2. Correspondingly the current density follows linear behavior no longer in the region between E 1 and E 2. A model based on the rearrangement of the particles under the electric field. which causes the variation of the dielectric property of the ER fluid, is proposed and the analysis is consistent with the measured results.

CHARACTERISATION OF THE COMPLEX SHEAR MODULUS PROPERTIES OF ELECTRO-RHEOLOGICAL FLUIDS BY THE DIRECT STIFFNESS AND MASTER CURVE TECHNIQUES

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3227-3236 ◽  
Author(s):  
S O Oyadiji
Keyword(s):  
Field Strength ◽  
Shear Modulus ◽  
Electric Field ◽  
Electric Field Strength ◽  
Loss Factor ◽  
Master Curve ◽  
Measured Temperature ◽  
Direct Stiffness ◽  
Er Fluid ◽  
Field Strengths

The direct stiffness technique was employed to characterise the complex modulus properties of a silicone oil-based electrorheological fluid over a frequency range from 30Hz to 300Hz and a temperature range from 0°C to 60ºC. The ER fluid device utilised was a set of concentric cylinders possessing a radial gap of 3mm between adjacent cylinders. Electric field strengths of between 0kV/mm and 2kV/mm were applied across the ER fluid. The results show that the shear modulus of the ER fluid decreased monotonically as the temperature was increased from 0ºC to 60ºC. Overall, the shear modulus decreased by a factor of up to 20. On the other hand, the shear loss factor increased from a low value of about 0.05 at 0ºC to a high value of about 1.0 at 60ºC. Conversely, as the electric field strength was increased from 0kV/mm to 2kV/mm, the shear modulus increased whereas the loss factor decreased. At all temperatures and electric field strengths of these investigations, both the shear modulus and loss factor increased in value as the excitation frequency was increased. The sets of measured temperature- and frequency-dependent data were converted, using the master curve technique, to master curves of shear modulus and loss factor which vary with frequency over several decades at a constant reference temperature and for varying levels of the electric field strength.

Properties and Structure of Ni/TiO2/Polar Molecule Core-Shell Particles Electrorheological Fluid

2012 ◽  
Vol 512-515 ◽  
pp. 2166-2170
Author(s):  
Suo Kui Tan ◽  
Xiao Ping Song ◽  
Hong Zhao ◽  
Song Ji ◽  
Li Qiao ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electrorheological Fluid ◽  
Polar Molecule ◽  
Fluid Properties ◽  
Structure Observation ◽  
Shell Particles ◽  
The Relationship ◽  
Er Fluid

By means of mechanical properties test and structure observation， the relationship among electric field strength, polar molecule type, content on the Ni/TiO2group electrorheological fluid properties have been analyzed. It is found that with increasing electric field strength，the properties of electrorheological fluid increased for same composition ER fluid. Different type polar molecules have distinct effect. For same particle，with increasing polar molecule content，the property is increased, but there is a critical value . Polar molecule make particles chain of electrorheological fluid become strong，coarse and interweaved each other.

TRANSIENT BEHAVIOR OF THE MICROSTRUCTURE OF ELECTRORHEOLOGICAL FLUIDS IN SHEAR FLOW MODE

2001 ◽  
Vol 15 (06n07) ◽  
pp. 695-703 ◽  
Author(s):  
S. L. VIEIRA ◽  
M. NAKANO ◽  
S. HENLEY ◽  
F. E. FILISKO ◽  
L. B. POMPEO NETO ◽  
...  
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Shear Flow ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Transient Behavior ◽  
Electrorheological Fluids ◽  
Flow Mode ◽  
Er Fluid

It was reported that under the simultaneous stimulus of an electric field and shear, the particles in an ER fluid form lamellar formations in the direction of shear (adhered to one of the electrodes) which may be responsible for the ER activity more than the strength of the chains. In this way, it would be expected that the shear stress should change consistently with the morphology of the formations. In this work we studied the effect of shearing time, electric field strength and shear rate on the shear stress. We suggest that changes on shear stress with time are due to changes of the morphology of the lamellar formations.

Electrorheological Properties of Suspensions Prepared From Polythiophene Conductive Polymer

Materials ◽  
2005 ◽  
Author(s):  
Datchanee Chotpattananont ◽  
Anuvat Sirivat
Keyword(s):  
Shear Flow ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Applied Stress ◽  
Volume Fraction ◽  
Scaling Law ◽  
Oscillatory Shear ◽  
Steady Shear ◽  
Er Fluid

Electrorheological (ER) fluids are typically composed of polarizable particles dispersed in a non-conducting fluid. Upon the application of an electric field, chain-like or fibrillar aggregates of the suspended particles are oriented along the direction of the electric field, thereby inducing viscoelasticity and a drastic increase in viscosity. In our study, Poly(3-thiophene acetic acid), PTAA, has been developed for using as ER material. The rheological properties of this PTAA suspension upon the application of electric field were investigated under various deformations; oscillatory shear flow, steady shear, and creep. We found that PTAA based ER fluid exhibited viscoelastic behavior and showed the excellent responses under an applied electric field. Moreover, the ER response of this PTAA fluid was amplified with increases in electric field strength, particle concentration, and particle conductivity. Under the oscillatory shear, the dynamic moduli, G′ and G″, increased dramatically by 10 orders of magnitude, when the field strength was increased to 2 kV/mm. The suspensions exhibited a transition from fluid-like to solid-like behavior as the field strength increased. While under steady shear flow, the yield stress increased with electric field strength, E, and particle volume fraction, φ, according to a scaling law of the form, τy α Eαφγ. Furthermore, the creep curves of this ER fluid consisted of both elastic and viscous responses and this fluid exhibits partially elastic recovery after the removal of applied stress. The creep properties strongly depended on the magnitude of an applied stress.

MECHANICAL PROPERTIES OF AN ER FLUID IN TENSILE, COMPRESSION AND OSCILLATORY SQUEEZE TESTS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 714-722 ◽  
Author(s):  
S. L. VIEIRA ◽  
M. NAKANO ◽  
R. OKE ◽  
T. NAGATA
Keyword(s):  
Mechanical Properties ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Silicone Oil ◽  
Strain Curve ◽  
Mechanical Tests ◽  
Damping Force ◽  
Carbonaceous Particles ◽  
Er Fluid

In this work, the mechanical properties of an anhydrous electrorheological fluid made of carbonaceous particles dispersed in silicone oil were determined in tensile, compression and oscillatory squeeze tests. The mechanical tests were carried out on a Mechanical Testling Machine and the device developed for measuring the ER properties was composed of two parallel steel electrodes between which the ER fluid was placed. The mechanical properties were measured for different DC electric field strengths, velocity and initial gap between the electrodes, and the ERF was tested in two different ways: (a) the fluid was placed between the electrodes (configuration 1) and (b) the electrodes were immersed inside the ERF (configuration 2). The results showed that the ER fluid is more resistant to compression than to tensile, and that the shape of the tensile stress-strain curve and the tensile strength varies with the electric field strength and the initial gap between the electrodes. The compressive stress increased with the increase of the electric field strength and with the decrease of the gap size and upper electrode velocity. In oscillatory test, for both configurations 1 and 2, increasing the oscillation frequency f and the number of cycles N produced a decrease of the damping performance of the ER fluid. Besides this, the damping force of each cycle in oscillatory tests increased with N. The electric field also played an important role on the shape of the hysteresis loop (stress as a function of fluid strain) for both configurations.

Optical Measurement of the Electric Field Strength in a Gel Insulator

2016 ◽  
Vol 136 (10) ◽  
pp. 1420-1421
Author(s):  
Yusuke Tanaka ◽  
Yuji Nagaoka ◽  
Hyeon-Gu Jeon ◽  
Masaharu Fujii ◽  
Haruo Ihori
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Optical Measurement

Effect of external magnetic field on lane formation in driven pair-ion plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Swati Baruah ◽  
U. Sarma ◽  
R. Ganesh
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Coupling Parameter ◽  
Critical Parameters ◽  
Coulomb Coupling ◽  
Lane Formation ◽  
Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

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