Water-Activated Bacterial Cellulose-Based Electrorheological Fluids and Electromechanical Response of Artificial Muscle Based on Electrorheological Fluids and Siloxane Gel

2009 ◽  
Vol 87-88 ◽  
pp. 143-148
Author(s):  
Nai Xu ◽  
De Min Jia
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Bacterial Cellulose ◽  
Yield Stress ◽  
Particle Concentration ◽  
Electrorheological Fluids ◽  
Water Yield ◽  
Composite Gel

Electrorheological (ER) characteristics of ER fluids (ERF) containing bacterial cellulose (BC) particles in silicone oil was investigated as a function of particle water content, DC electric field strength and particle concentration. It was found that the existence of water in BC particles strongly influenced the performance of water-activated ERF based on BC particles. Around 8.8 wt% water, yield stress reached its maximum valve of 1118 Pa after which it decreased with increasing water content. At the same water content, yield stress increased linearly with increasing in either electric field strength or particle concentration. The ERF based on BC particles was introduced into the poly (dimethylsiloxane) (PDMS) gels to prepare electric field sensitive composite gel. Electric fields were applied to these composite gels using flexible electrodes. Compressions of these gels with varying PDMS/ERF ratios were confirmed by the electrode displacement. It was found that 50/50 PDMS/ERF gel exhibited the maximum displacement of 102um at 2 kV/mm electric field.

scholarly journals Experimental Study on the Performance of a Novel Compact Electrostatic Coalescer with Helical Electrodes

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1733
Author(s):  
Yi Shi ◽  
Jiaqing Chen ◽  
Zehao Pan
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Water Droplet ◽  
Separation Process ◽  
Water Droplets ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

As most of the light and easy oil fields have been produced or are nearing their end-life, the emulsion stability is enhanced and water cut is increasing in produced fluid which have brought challenges to oil–water separation in onshore and offshore production trains. The conventional solution to these challenges includes a combination of higher chemical dosages, larger vessels and more separation stages, which often demands increased energy consumption, higher operating costs and larger space for the production facility. It is not always feasible to address the issues by conventional means, especially for the separation process on offshore platforms. Electrostatic coalescence is an effective method to achieve demulsification and accelerate the oil–water separation process. In this paper, a novel compact electrostatic coalescer with helical electrodes was developed and its performance on treatment of water-in-oil emulsions was investigated by experiments. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters and number of droplets within a certain size range are set as indicators for evaluating the effect of coalescence. We investigated the effect of electric field strength, frequency, water content and fluid velocity on the performance of coalescence. The experimental results showed that increasing the electric field strength could obviously contribute to the growth of small water droplets and coalescence. The extreme value of electric field strength achieved in the high-frequency electric field was much higher than that in the power-frequency (50 Hz) electric field, which can better promote the growth of water droplets. The initial average diameters of water droplets increase with higher water content. The rate of increment in the electric field was also increased. Its performance was compared with that of the plate electrodes to further verify the advantages of enhancing electrostatic coalescence and demulsification with helical electrodes. The research results can provide guidance for the optimization and performance improvement of a compact electrocoalescer.

Electrorheological Response of Polyaniline Particles Embedded in Cross-Linked Poly(Dimethyl Siloxane) Networks

Materials ◽  
2005 ◽  
Author(s):  
Piyanooth Hiamtup ◽  
Anuvat Sirivat
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Crosslink Density ◽  
Particle Concentration ◽  
Shear Mode ◽  
Zero Field ◽  
Dimethyl Siloxane ◽  
The Matrix ◽  
Electromechanical Responses

Electrorheological characteristics of poly (dimethyl siloxane) (PDMS) networks containing camphorsulfonic acid (CSA) doped-polyaniline (PANI) particles were investigated. Samples were prepared by dispersing fine polyaniline particles into cross-linked PDMS. Rheological properties of the PANI/PDMS blends were studied in the oscillatory shear mode in order to study the effects of electric field strength, crosslink density of the matrix, particle concentration, and operating temperature on their electromechanical responses. The electrostriction of the blends were observed as a result of an attractive force among polarized particles embedded in the network. The sensitivity values of blends are defined as the storage moduli at any applied electric field subtracted by those values at zero electric field, and divided by the moduli at zero field. They were found to increase about 10-50% when electric field strength was increased to 2 kV/mm. These moduli values increased with particle concentration and temperature but they decreased with crosslink density of the matrices.

Mechanical Properties of Complex Structure Formed From Electro-Convection State of Smectic Liquid Crystal

2011 ◽  
Author(s):  
Takatsune Narumi ◽  
Hideaki Hoshi ◽  
Tomohiko Muraki ◽  
Tomiichi Hasegawa
Keyword(s):  
Liquid Crystal ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Yield Stress ◽  
Electric Fields ◽  
Complex Structure ◽  
Small Deformation ◽  
Small Strain ◽  
Control Mode

In the present study, electro-rheological characteristics of a liquid crystal (8CB) in smectic-A phase were investigated utilizing a parallel-plate type rheometer under a stress control mode. Solid like behaviors of the liquid crystal under DC electric fields were mainly examined. Bingham-like properties were observed and yield stresses measured were affected with the electric field conditions. When the electric field strength was low, the yield stress was almost the same as that obtained under no electric field. Above a threshold of DC electric field strength, the yield stress increased. It was clarified that the increase in the yield stress was caused with the complex structure formed in cooling process from an electro-convection state in nematic phase. Mechanical property changes after deformation of the structure were also examined as changes in dynamic viscoelasticities under condition of very small strain amplitude and the yield stress. The properties were measured before and after the deformation and compared. Moreover, the deformed structure of the liquid crystal was visualized with a polarizing microscope. Since the initial structures formed after the cooling have unevenness, the strength of the structure varied widely. When the small deformation is applied, peculiar changes in the strength were observed, i.e. the G’ measured was increased or decreased after the deformation. Moreover, the values measured after the deformation had reproducibility despite of the scattered initial data. We observed growth of typical optical patterns in the visualization of the structure and it is considered that defects like focal conic domains were generated and developed. After large deformation, the strength of the structure decreased and the deformed structure had almost no elastic properties. The structures were changed to irregular flow structures.

Response Surface Method Analysis on Electro-Enhanced Technique for Remediation of Cadmium Contaminated Soil

2020 ◽  
Vol 980 ◽  
pp. 502-511
Author(s):  
Yu Shan Wan ◽  
Ju An Zhai ◽  
An Wei Wang
Keyword(s):  
Energy Consumption ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Content ◽  
Contaminated Soil ◽  
Removal Rate ◽  
Electrokinetic Remediation ◽  
Surface Method ◽  
Remediation Time

In view of the problems of long remediation time, high energy consumption and low remediation efficiency in electrokinetic remediation of heavy metal contaminated soil, Cd was used to simulate heavy metals in contaminated soil, and response surface method (RSM) was used to optimize the factors influencing electrokinetic remediation. Central Composite (CCD) experimental design method was taken to study the effects of electric field strength, remediation time and water content on removal rate of Cd in soil. Also, polynomial regression mathematical model and optimal reaction conditions were provided for Cd pollution in electrokinetic soil remediation. The simulated equation F was 15.67, the correlation coefficient was 0.9338, and the adjustment correlation coefficient was 0.9042, indicating good regression and strong significance of the equation. The model results showed that, for the optimal experimental conditions, electric field strength was 2.25V·cm-1, the remediation time was 120.79h, and the water content was 17.06%. On the basis of such reaction condition, intermittent current flow method was adopted d to further enhance the electrokinetic remediation effect. The cadmium removal rate in the soil was increased by 3.17%, 2.86% and 2.43%, respectively, and the electric energy consumption was decreased by 10.54%, 11.28% and 9.97%, respectively, suggesting that the method could effectively improve the removal rate of Cd and reduce energy consumption.

Investigation of Thermal Conductivity of Alumina/Silicone Oil Electrorheological Fluids

2010 ◽  
Vol 129-131 ◽  
pp. 421-425 ◽  
Author(s):  
Yi Chun Wang ◽  
Xiao Xia Sun ◽  
Xiao Rong Tang ◽  
Fa Cheng Wang
Keyword(s):  
Thermal Conductivity ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Silicone Oil ◽  
Conductivity Measurement ◽  
Electrorheological Fluids ◽  
High Voltage Power Supply ◽  
Heating Device ◽  
Er Fluids

Electrorheological (ER) fluids are new materials with good properties such as dielectric constant, dielectric loss or conductivity, which display remarkable rheological behavior, being able to convert rapidly and repeatedly from a liquid to solid when an electric field is applied or removed. In this study, suspensions of alumina (A) were prepared in silicone oil (SO). The effects of electric field strength and temperature of the suspensions on thermal conductivity were determined. Thermal conductivity measurement in different conditions was carried out via experimental instrument with high-voltage power supply and water heating device to investigate the effects of electric field strength and temperature on ER performance and thermal conductivity. The results show that the thermal conductivity is in accordance with ER properties enhanced by increasing the field strength and decreasing the temperature.

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.

scholarly journals Parameters of Nanosecond Overvoltage Discharge Plasma in a Narrow Air Gap between the Electrodes Containing Electrode Material Vapor

2018 ◽  
Vol 63 (9) ◽  
pp. 790
Author(s):  
O. K. Shuaibov ◽  
O. Y. Minya ◽  
M. P. Chuchman ◽  
A. O. Malinina ◽  
O. M. Malinin ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electrode Material ◽  
Particle Concentration ◽  
Discharge Plasma ◽  
Simulation Method ◽  
Air Gap ◽  
Copper Vapor

Parameters of the nanosecond overvoltage discharge plasma in an air gap of (1÷5) × 10−3 m between the electrodes, which contains the vapor of an electrode material (Zn, Cu, Fe) injected into plasma due to the ectonic mechanism, have been studied. The dependences of those parameters on the ratio E/N between the electric field strength E and the particle concentration N in the discharge are calculated for the “air–copper vapor” system, by using the numerical simulation method.

Electrorheological Fluid Hysteresis

Materials ◽  
2005 ◽  
Author(s):  
Young Dae Kim ◽  
Daniel De Kee
Keyword(s):  
Shear Rate ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Particle Concentration ◽  
Electrorheological Fluid ◽  
Particle Structure ◽  
Hysteresis Behavior ◽  
Precise Control ◽  
Er Fluids

Electrorheological (ER) fluids are suspensions of polarizable particles dispersed in insulating liquids. They exhibit a rapid and reversible transition from a liquid-like to a solid-like state upon the application of an electric field. The observed shear stress - shear rate hysteresis makes the precise control of the ER mechanical devices very difficult. Hysteresis behavior of TiO2 ER fluids were observed by varying particle concentration, electric field strength, maximum shear rate, and the time of hysteresis loop. In the absence of an electric field, the stress level of the up curve exceeds that of the down curve. The presence of an electric field, reverses this trend. The extent of hysteresis becomes more significant with increasing electric field strength, particle concentration, and maximum shear rate. Hysteresis behavior of TiO2 ER fluids seems to arise mainly due to the change of the particle structure during shearing. To describe the complex rheological behavior of ER fluids, a kinetic theory is presented. Model predictions show qualitative agreement with the experimental hysteresis data.

CHARACTERISTICS OF A YIELD STRESS SCALING FUNCTION FOR ELECTRORHEOLOGICAL FLUIDS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2636-2642 ◽  
Author(s):  
H. J. CHOI ◽  
J. W. KIM ◽  
M. S. CHO ◽  
C. A. KIM ◽  
M. S. JHON
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Yield Stress ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Critical Evaluation ◽  
Particle Volume ◽  
Scaling Equation ◽  
Er Fluids

The electrorheological (ER) fluids exhibit a drastic change in rheological and electrical properties. Among these properties, yield stress is one of the critical evaluation parameters of the performance of ER devices. The published experimental data of yield dependence on the electric field strength and particle volume fraction are inconsistent due to the time dependence of material properties and measuring conditions. In this paper, we present a universal function, descriptive of the normalized yield stress, via scaling of the applied electric field strength. This scaling equation hybridizes both the polarization and conductivity models. Yield stress data for various ER fluids are collapsed onto a single curve for a broad range of electric field strengths, suggesting that the proposed scaling equation is adequate for predicting the ER property. Furthermore, the yield stresses, obtained from two different measuring techniques (static and dynamics methods), were also examined.

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