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.

EFFECT OF DIELECTRIC PROPERTY OF HYDROUS DISPERSOID ON ELECTRORHEOLOGY

1996 ◽  
Vol 10 (23n24) ◽  
pp. 2849-2855 ◽  
Author(s):  
Akiko KAWAI ◽  
Kunio UCHIDA ◽  
Kunio KAMIYA ◽  
Akihiro GOTOH ◽  
Satoshi YODA ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Property ◽  
Dielectric Loss ◽  
Water Content ◽  
Loss Factor ◽  
Free Water ◽  
Relaxation Frequency ◽  
Dielectric Loss Factor ◽  
Silicon Oil

The effect of the dielectric property was investigated of titania and microcrystalline cellulose particles dispersed in a silicon oil on Electrorheology(ER). A commom understanding of the mechanism of ER is the electrical interaction by the interfacial polarization of dispersed particles. Block et al. reported the relaxation frequency of ER fluids, i. e. the rate of polarization, was very important to have an appreciable ER effect. We found that the free water on the cellulose and the titania particles dispersed in the silicon oil, which is respectively dehydrated below the temperature of ca. 110 and 300 degree centigrade, was necessary for an appreciable ER effect. The relation was measured between the water content and the dielectric properties such as dielectric constant ε ’ and dielectric loss factor ε ", as the water adsorbed on the particles was estimated to alter the dielectric properties of the ER fluid. Both the dielectric constant and the relaxation frequency, which is defined by the applied frequency for a peak of the dielectric loss factor, increased with the increase of the water content The relation was discussed between the ER effect and the dielectric properties.

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.

ELECTRORHEOLOGICAL BEHAVIOR OF CHITOSAN DERIVATIVE SUSPENSIONS

2001 ◽  
Vol 15 (06n07) ◽  
pp. 1025-1032 ◽  
Author(s):  
Ung-su Choi ◽  
Byeng-gil Ahn ◽  
Oh-kwan Kwon
Keyword(s):  
Electric Field ◽  
Volume Fraction ◽  
Silicone Oil ◽  
Flow Behavior ◽  
Chitosan Derivative ◽  
Shear Yield Stress ◽  
Bingham Flow ◽  
Shear Yield ◽  
The Difference ◽  
Er Fluid

The electrorheological (ER) behavior of chitosan and chitosan phosphate suspensions in silicone oil was investigated. Chitosan and chitosan phosphate suspensions showed a typical ER response (Bingham flow behavior) upon application of an electric field. However, chitosan phosphate suspension exhibited excellent shear yield stress compared with chitosan suspension. The difference in behavior results from the difference in the conductivity of the chitosan and chitosan phosphate particles due to their degree of the polarizability. The shear stress for chitosan and chitosan phosphate suspensions showed a linear dependence on the volume fraction of particles. The values of structure factor, A s obtained 1 and 3~4 for chitosan and chitosan phosphate suspensions and it may be due to the formation of single-row chains and multiple chains upon application of the electric field. Throughtout the experimental results, chitosan and chitosan phosphate suspensions were shown to be an ER fluid.

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.

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.

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.

The Effect of the Coating Layer and the Doped Ion Concentration on the Dielectric Properties of SiO2-PANI Electrorheological Fluid

2010 ◽  
Vol 663-665 ◽  
pp. 523-526
Author(s):  
Wei Zhou ◽  
Seng Liang ◽  
Yue Mei Sun
Keyword(s):  
Dielectric Properties ◽  
Silicon Dioxide ◽  
Coating Layer ◽  
Electrorheological Fluid ◽  
Relaxation Frequency ◽  
Ion Concentration ◽  
Impedance Analyzer ◽  
Dielectric Increment ◽  
Er Fluids ◽  
Er Fluid

The silicon dioxide particles are coated by polyaniline (PANI) under low temperature, and the doped ion concentration in PANI was adjusted by ammonia with different pH. The dielectric properties of PANI/SiO2 eletrorheological (ER) fluids are measured by impedance analyzer. The results indicated that the dielectric increment and relaxation frequency of ER fluid were enhanced after surface modification of SiO2, which are positive to the ER effect. Moreover, the pH of ammonia can change the relaxation frequency of ER fluid, which can improve the response ability of ER fluid to electric field.

EFFECTS OF SHAPE AND SIZE OF DISPERSOID ON ELECTRORHEOLOGY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2548-2554 ◽  
Author(s):  
AKIKO KAWAI ◽  
KUNIO UCHIDA ◽  
FUMIKAZU IKAZAKI
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Dielectric Properties ◽  
Dielectric Property ◽  
Zinc Complexes ◽  
Zinc Oxides ◽  
Different Shapes ◽  
Er Fluid ◽  
Shape And Size

The effects of shape and size of dispersoids on electrorheology were investigated. In order to study the effect of shape on electrorheology, three kinds of hydroxy-zinc complexes were used for dispersoids. Hydroxy-zinc complexes were Zn 5 (OH) 8 Cl 2 · H 2 O (1), Zn 5 (OH) 8( NO 3)2 · 2H 2 O (2), and Zn 5 (OH) 8( CH 3 COO )2 · 2H 2 O (3). Shapes of (1) and (2) are plate. The shape of (3) is rod. The ER fluid containing (3) showed the lowest permittivity and the lowest ER effect. The ER phenomena containing dispersoids with different shapes were independent of their shapes and were explained by their dielectric properties. Zinc oxides prepared by the heat treatment of (1), (2), and (3) were used for studying the effect of size on electrorheology. The particle size influenced their dielectric property and influenced their electrorheology. The dielectric properties were responsible for the ER effect.

scholarly journals Effect of Different Moisture Content on Mechanical Parameters of Red Clay Under Freeze-Thaw Cycle

2021 ◽  
Author(s):  
Bin Lin ◽  
Zhuhua Tian ◽  
Liang Jiang ◽  
Yongjia Zhao
Keyword(s):  
Shear Stress ◽  
Elastic Modulus ◽  
Water Content ◽  
Clay Soil ◽  
Poisson Ratio ◽  
Friction Angle ◽  
Mechanical Parameters ◽  
Red Clay ◽  
Freeze Thaw ◽  
The Difference

Abstract One of the causes of damage in cold area projects is the freeze-thaw cycling action, which causes large changes in soil strength, resulting in soil deformation and destroying its soil stability. In order to investigate the effect of water content on the mechanical parameters of red clay soil under the action of freeze-thaw cycles, the solidification undrained triaxial test and consolidation test were carried out with red clay soil in Changzhi area, Shanxi Province, as the research object. The test results show that the stress-strain curve is hardening curve, with the increase of water content, the maximum shear stress, cohesion, internal friction angle, elastic modulus, compression modulus and shear modulus are decreasing, and Poisson ratio is gradually increasing. The mechanical parameters of 0 freeze-thaw cycles are greater than 12 freeze-thaw cycles. With the increase in water content, the difference in shear stress between two freeze-thaw cycles was decreasing under the same circumferential pressure. 0 freeze-thaw cycles, the decreasing trend of cohesion increased from 4.48% to 35.88%, and the elastic modulus decreased up to 69.61%. 12 freeze-thaw cycles, the decreasing trend of cohesion decreased from 65.38% to 5.93%, and the elastic modulus showed a linear decreasing relationship. The decreasing trend of the internal friction angle remained consistent with the gradual increase. The Poisson ratio was 0.21-0.29 and 0.24-0.31 for the two cycles, respectively. The shear modulus at 0 freeze-thaw cycles was 1.86-1.16 times higher than that at 12 freeze-thaw cycles, and the difference decreased gradually with the increase in water content. The increase in water content made the soil more prone to shear deformation.

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