YIELD PROCESS OF ELECTRORHEOLOGICAL FLUID WITH POLYANILINE PARTICLE

1994 ◽  
Vol 08 (25) ◽  
pp. 1563-1575 ◽  
Author(s):  
KIYOHITO KOYAMA ◽  
KEIJI MINAGAWA ◽  
TAMOTSU YOSHIDA ◽  
NORIYUKI KURAMOTO ◽  
KATSUFUMI TANAKA
Keyword(s):  
Shear Stress ◽  
Electric Field ◽  
Particle Concentration ◽  
Silicone Oil ◽  
Electrorheological Fluid ◽  
Yield Behavior ◽  
Wide Range ◽  
Dc Electric Field ◽  
Er Fluid ◽  
Flow Experiments

Electrorheological behaviors of polyaniline/silicone oil suspension were observed by using a modified Couette type rheometer with high resolution for shear stress. The yield behaviors were examined over a wide range of shear strain. The storage modulus and loss tangent were determined under a constant dc electric field. It was clarified that the polyaniline-based ER fluid yields two different strain amplitudes, i.e. about 1% and 50%. The stress-strain curves obtained from shear flow experiments also suggested the existence of two-step yield process. The yield process was found to be dependent on the electric field strength and the particle concentration in different manners. The yield behavior observed is discussed in relation to the structure of particle clusters which causes the ER effect.

ELECTRORHEOLOGY OF DISPERSIONS OF BaxSr(1-x)TiO3 IN SILICONE OIL UNDER AC OR DC ELECTRIC FIELD

2012 ◽  
Vol 26 (14) ◽  
pp. 1250081 ◽  
Author(s):  
GLAUBER M. S. LUZ ◽  
ANTONIO J. F. BOMBARD ◽  
SILVIO L. M. BRITO ◽  
DOUGLAS GOUVÊA ◽  
SHEILA L. VIEIRA
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Electric Field ◽  
Silicone Oil ◽  
Ferroelectric Materials ◽  
Dc Electric Field ◽  
Ac Fields ◽  
Er Fluid ◽  
Constant Shear Rate

Electrorheology (ER) of ferroelectric materials such as nanometric BaTiO 3 is still not fully understood. In this paper, nanoparticles of Ba x Sr (1-x) TiO 3 (where x = 0.8, 0.9 or 1.0) were synthesized using the method of Pechini, calcinated at 950°C, and after, lixiviated under pH 1 or pH 5. A controlled stress rheometer (MCR-301) was used to make the ER characterization of dispersions made of Ba x Ti 1-x O 3 in silicone oil (30% w/w), where (a) shear stress as a function of DC electric field (under constant shear rate) or (b) shear stress as a function of shear rate (under constant AC or DC electric field) were measured. We observed that electrophoresis occurred under electric field DC, creating a concentration gradient which induced phase separation in ER fluid. On the other hand, under AC fields above 1 kV/mm, the ER effect is stronger than for DC field, and almost without electrophoresis. Furthermore, there is an AC frequency, dependent on the disperse phase, where the ER effect has a maximum.

Measurement of Interaction Forces at Small Distance under Electric Field in a Smectite Dispersed Silicone Oil Based ER Fluid

2001 ◽  
Vol 15 (06n07) ◽  
pp. 811-816 ◽  
Author(s):  
Toyohisa FUJITA ◽  
Toshio MIYAZAKI ◽  
Toshiharu TANAKA ◽  
Ke Jun Liu ◽  
Eiich KUZUNO ◽  
...  
Keyword(s):  
Electric Field ◽  
Silicone Oil ◽  
Small Distance ◽  
Surface Forces ◽  
Attraction Force ◽  
Interaction Forces ◽  
Repulsive Energy ◽  
Inflection Points ◽  
Dc Electric Field ◽  
Er Fluid

The apparatus to measure interaction forces under an electric field at small distance between a conductive hemisphere and a flat plate has been developed. The surface forces at small distance sandwiched ER fluid dispersing ultrafine smectite particles (20 to 50 nm thickness) in silicone oil has been measured. This fluid shows 0.7 kPa of apparent yield stress by applying 2.5 kV/mm of DC electric field. When an electric field applies to this ER fluid, the repulsive energy curves shows inflection points at about 0.2 μ m distance periodically at small distance of less than 1 μ m because the repulsion force decreases for a vacancy of particles after the particles are pushed out and the dipole attraction force acts between hemisphere and plate. On the other hand, when the electric field becomes off and it passes enough time, the inflection points is observed more shorter distance of about 0.15 μ m periodically. The coagulated particle size is estimated about 0.15 μ m under no electric field and becomes larger by applying electric field.

ELECTRORHEOLOGICAL BEHAVIORS OF POLYANILINE-MONTMORILLONITE CLAY NANOCOMPOSITE

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2521-2527 ◽  
Author(s):  
JUN LU ◽  
XIAOPENG ZHAO
Keyword(s):  
Dielectric Constant ◽  
Shear Stress ◽  
Electric Fields ◽  
Room Temperature ◽  
Silicone Oil ◽  
Weight Fraction ◽  
Influential Factors ◽  
Dc Electric Field ◽  
Er Fluid ◽  
Xrd And Tem

Polyanilline-montmorillonite nanocomposite (PANI-MMT) particles were synthesized by an emulsion intercalation method and characterized by IR, XRD and TEM spectrometry. TEM showed that the particle's size of MMT-PANI particles was about 100 mm. The dielectric constant of PANI-MMT nanocomposite was increased 2.4 times than that of MMT and 7 times than PANI, the conductivity of PANI-MMT particles was increased was increased 10 times than that of MMT. Meanwhile, the dielectric loss tangent was also increased about 1.36 times than that of PANI. The electrorheological behaviors of the suspensions of PANI-MMT nanocomposite in silicone oil with a 30% weight fraction were investigated under DC electric fields. In 3 kV/mm DC field at room temperature, the yield stress was 8.26 kPa (shear 5 s -1). In 4 kV/mm DC field, the shear strength was 8.30 kPa (γ = 103.1 s -1, T = 20°C), and much higher than that of pure polyaniline (PANI), montmorillonite (MMT) and mixture of polyaniline with clay (MMT + PANI). The sedimentation experiment showed that the PANI-MMT nanocomposite particles did not deposit during about two months. The relevant influential factors between shear stress and electric fields, between shear stress and shear rate, between shear stress and temperature was also discussed preliminarily. The results showed that the MMT-PANI ER fluid displays a notable ER effect under DC electric field.

EFFECT OF RARE EARTH SUBSTITUTION ON ELECTRORHEOLOGICAL PROPERTIES OF TiO2

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2371-2377 ◽  
Author(s):  
X. P. ZHAO ◽  
J. B. YIN ◽  
L. Q. XIANG ◽  
Q. ZHAO
Keyword(s):  
Shear Stress ◽  
Rare Earth ◽  
Silicone Oil ◽  
Anatase Phase ◽  
New Class ◽  
Dc Electric Field ◽  
Er Fluids ◽  
Er Fluid ◽  
Electrorheological Properties ◽  
Rare Earth Substitution

This paper describes a new class of water-free electrorheological (ER) fluids based on nonaqueous doped TiO 2 with rare earth (RE) in silicone oil. The thermal character and crystal structure of these materials are investigated with DSC, TG and XRD. The doped TiO 2 crystals possess anatase phase and their lattice spacing varies significantly with the content of rare earth. The rheological measurements show that the doped TiO 2 ER fluid exhibits an obviously higher shear stress than that of pure TiO 2 ER fluid under dc electric field. Especially, substitution with 10mol% cerium or 8mol% lanthanum for Ti can obtain a relatively high shear stress. On the basis of dielectric and conduction measurements, we preliminarily discuss the influence of the doping of rare earth on ER effects of TiO 2.

Investigation into Electrorheological Fluid-Assisted Polishing Optical Glass

2011 ◽  
Vol 110-116 ◽  
pp. 1099-1106
Author(s):  
Yun Wei Zhao ◽  
De Xu Geng ◽  
Xiao Min Iu ◽  
Jin Tao Zhang
Keyword(s):  
Electric Field ◽  
Silicone Oil ◽  
Optical Glass ◽  
Electrorheological Fluid ◽  
Abrasive Particles ◽  
Micro Tool ◽  
Ultra Precision ◽  
Aspherical Lenses ◽  
Field Lines ◽  
Er Fluid

Electrorheological (ER) fluid-assisted polishing process is the ultra precision finishing technologies for micro-aspherical lenses and dies. The principle of ER fluid-assisted polishing (ERP) is to use ER effect as a result of the application of electric field. The ER particles and abrasive particles suspended in silicone oil are polarized in which ER particles strongly attract each other and aggregate into chain like structure along the electric field lines, and the abrasive particles may adhere to the ER chain. The force acting on ER particles and abrasive particles in an electric field is calculated. Furthermore, experiments of polishing optical glass with Al2O3 are carried out to find the influential regularities of polishing time, rotational speed of micro-tool, voltage, the density of abrasives in ER fluid on the surface roughness.

Electrorheology of Suspension of Sulfonated Styrene-Co-Divinylbenzene Particles — Approach Based on the Dielectric Properties of the Suspension —

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1845-1851 ◽  
Author(s):  
F. Ikazaki ◽  
A. Kawai ◽  
T. Kawakami ◽  
M. Konishi ◽  
Y. Asako
Keyword(s):  
Shear Stress ◽  
Dielectric Properties ◽  
Dielectric Property ◽  
Water Content ◽  
Particle Concentration ◽  
Silicone Oil ◽  
Relaxation Frequency ◽  
Measurement Temperature ◽  
The Difference ◽  
Er Fluid

Effects of particle concentration, water content and temperature on the electrorheology of suspensions of highly sulfonated styrene-co-divinylbenzene (SSD) particles in a silicone oil were investigated. The induced shear stress was measured with a modified rotary rheometer. The electrorheology of the suspension was largely affected by the particle concentration, the water content and the measurement temperature. The induced shear stress for the particle concentration of 40 wt% was about twice as large as that of 20 wt%. The induced shear stress for the water content of 4 wt% was about twice as large as that of 2 wt%. The induced shear stress for the temperature of 80°C was about 15 times as large as that of 20°C. Dielectric properties were measured to elucidate the mechanism of electrorheology. In order for an ER fluid to have large ER effect, relaxation frequency of the ER fluid should be between 100 and 105 Hz and the difference of the dielectric constant below and above the relaxation frequency (Δ∊′) must be large, which we refer to as the dielectric property mechanism. The relation between measured ER effect and dielectric property mechanism was discussed.

Shear stress tracking control of an electrorheological fluid considering hysteresis non-linearity

2004 ◽  
Vol 218 (2) ◽  
pp. 183-194 ◽  
Author(s):  
Y M Han ◽  
S B Choi
Keyword(s):  
Shear Stress ◽  
Tracking Control ◽  
Silicone Oil ◽  
Electrorheological Fluid ◽  
Preisach Model ◽  
Temperature Dependent ◽  
Model Inversion ◽  
Control Robustness ◽  
Discrete Manner ◽  
Er Fluid

This paper presents shear stress tracking control of an electrorheological (ER) fluid actuator subjected to the hysteresis non-linearity. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. The Couette-type electroviscometer is employed to achieve the field-dependent shear stress. The Preisach model for the PMA-based ER fluid is identified using experimental first-order descending (FOD) curves. A compensation strategy is then formulated in a discrete manner through the Preisach model inversion to achieve the desired shear stress of the ER fluid. A proportional-intergal-derivative (PID) feedback controller is also integrated with the compensator in order to guarantee control robustness to uncertainty due to temperature-dependent hysteresis variation. The tracking performance of the control strategy is experimentally evaluated for two different desired shear stress trajectories.

Breakups of an encapsulated surfactant-laden aqueous droplet under a DC electric field

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8905-8911 ◽  
Author(s):  
Muhammad Salman Abbasi ◽  
Ryungeun Song ◽  
Jinkee Lee
Keyword(s):  
Electric Field ◽  
Castor Oil ◽  
Silicone Oil ◽  
Double Emulsion ◽  
Emulsion Droplet ◽  
Dc Electric Field ◽  
Aqueous Droplet

We study the breakups of a surfactant-laden aqueous/silicone oil/castor oil double emulsion droplet under an electric field.

scholarly journals Effects of Fiber and Copper Particles on Conductivity and Breakdown Characteristics of Natural Ester and Mineral Oil under DC Voltage

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1818 ◽  
Author(s):  
Lin Cheng ◽  
Yi Jiang ◽  
Min Dan ◽  
Hao Wen ◽  
Yanqing Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Particle Concentration ◽  
Breakdown Strength ◽  
Mineral Oil ◽  
Movement Speed ◽  
Testing Time ◽  
Copper Particles ◽  
Hvdc Transmission ◽  
Dc Electric Field ◽  
Natural Ester

The converter transformer is a key equipment in high voltage direct current (HVDC) transmission system. Its oil-paper insulation system in the valve winding and outlet bushing experiences AC, DC, AC/DC, and transient impulse voltages simultaneously. The oil contamination problem is more serious under DC electric field. Therefore, it is significant to investigate the characteristic of particles motion and accumulation under DC electric field. In this paper, first, the movement and accumulation behavior of fiber particles and copper particles in mineral oil and natural ester were recorded and simulated. Then, the influence of fiber and copper particles on the oil conductivity was analyzed. Finally, the DC breakdown strength of mineral oil and natural ester with different particles concentration was compared. Results show that the movement speed of copper particles was larger than that of fiber particles. Fiber impurities were easy to form bridges in mineral oil, while there was no impurity bridge in natural ester. The current density of mineral oil containing particles is larger than that of the natural ester at the same testing time. The DC 50% probability breakdown voltages of oil samples containing fiber and copper particles decreased linearly with the increase of particle concentration, and the decrease rate of DC 50% probability breakdown voltages of oil containing copper particles were faster than that of oil containing fiber particles. Compared to pure mineral oil, the DC breakdown voltages corresponding to 50% probability of contaminated mineral oil showed a decrease from 11.9% to 22.5% when the fiber particle concentration increased from 0.001% to 0.012%. The DC 50% probability breakdown voltages of contaminated mineral oil with copper particles decreased from 23.8% to 45.0% when the particle concentration increased from 0.1 g/L to 1.5g/L. However, the decline range of the figures for natural ester contaminated by fiber or copper particles showed a smaller drop.

ER Properties of a Suspension of Polymer Graft Carbon Black Particles

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1682-1688
Author(s):  
Masayoshi Konishi ◽  
Teruhisa Nagashima ◽  
Yoshinobu Asako
Keyword(s):  
Shear Stress ◽  
Carbon Black ◽  
Electric Field ◽  
Silicone Oil ◽  
Average Particle Size ◽  
Average Particle ◽  
Zero Field ◽  
Average Value ◽  
Time Period ◽  
Micron Size

We newly developed ER particles with sub-micron size. The particle was polymer graft carbon black (GCB1) composed of carbon black particles and a polymer. The average particle size of GCB1 was found to be 81 nm. An ER suspension (ER1) was obtained by mixing GCB1 (30 wt%) with silicone oil (70 wt%). The ER1 showed excellent dispersion stability. Further, GCB1 particles did not settle under centrifuging at 9000G. The zero-field viscosity was 80 mPa·s at 25°C. The kinetic friction coefficient of ER1 was 0.15, while that of the silicone oil used was 0.23. When the electric field of 3 kV/mm (AC 1000 Hz) at the temperature of 25°C and the shear rate of 700 s -1 was applied to ER1, the shear stress of 116Pa was induced. The induced shear stress did not change for a long period of time period. In the temperature range between 25 and 150°C the induced shear stress and the current density were almost constant at any electric field. When 3 kV/mm (AC 50Hz) at 25°C and 700s-1 was applied to ER1, the shear stress of 88Pa was induced but the deviation of the induced shear stress from the average value was pluses and minuses 3 Pa.

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