HYSTERESIS PHENOMENON IN FLOW-CURVES OF ER FLUIDS CONTAINING SULFONATED POLYMER PARTICLES

The ER fluids containing sulfonated polymer particles were continuously sheared at increasing and decreasing shear rates using a rotary concentric cylinder rheometer and the hysteresis in the up- and down-flow-curves were analyzed. The ER fluids show hysteresis of shear stress and current density. The up-curve (when shear rate increased) was located below the down-curve (when shear rate decreased). As the electric field increased, the area in the hysteresis curves increased. The hysteresis depended on the electric field strength, the time of the applied electric field, the volume fraction of particles and the water content of the particles. Hysteresis phenomenon was explained, based on the formation of agglomerations of dispersed particles in the ER fluid and on changes of the lamellar formations

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INFLUENCE OF SURFACTANTS ON PROPERTIES OF ELECTRORHEOLOGICAL FLUIDS CONTAINING POLYANILINE

International Journal of Modern Physics B ◽

10.1142/s0217979202012517 ◽

2002 ◽

Vol 16 (17n18) ◽

pp. 2461-2467 ◽

Cited By ~ 5

Author(s):

MAŁGORZATA BOCIŃSKA ◽

HENRYK WYCIŚLIK ◽

MARCIN OSUCHOWSKI ◽

JANUSZ PŁOCHARSKI

Keyword(s):

Yield Stress ◽

Current Density ◽

Silicone Oil ◽

Flow Curves ◽

Different Types ◽

Order Of Magnitude ◽

Dynamic Yield ◽

Rate Of Sedimentation ◽

Er Fluids

Sedimentation which is a natural process in most of ER fluids can be reduced by addition of surfactants that influence also other properties of the fluids. To study both the ER effect and the rate of sedimentation was the aim of the investigations. The ER fluids comprised powdered polyaniline and silicone oil to which surfactants of different polarity were added. The rate of sedimentation was measured by a sedimentation balance. The flow curves were recorded under electric field up to 2.5 kV/mm. Current density was also measured as a function of shear rate. It was found that the activity of a surfactant depends strongly on its polarity. The lipophylic surfactants stabilized the suspension very well but about 30% decrease of the dynamic yield stress was observed. The current density was reduced as well by almost one order of magnitude. The hydrophylic surfactants hardly stabilized the suspension but increase of yield stress was observed that was not followed by increase of current density. The role of different types of non-ionic surfactants was discussed.

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ELECTRORHEOLOGICAL EFFECT OF CONDUCTIVE POLYMERS DISPERSED IN LIQUID CRYSTALLINE MATRIX

International Journal of Modern Physics B ◽

10.1142/s0217979205029973 ◽

2005 ◽

Vol 19 (07n09) ◽

pp. 1135-1141 ◽

Cited By ~ 2

Author(s):

MONIKA CISZEWSKA ◽

JANUSZ PLOCHARSKI

Keyword(s):

Liquid Crystalline ◽

Silicone Oil ◽

Crystalline Polymer ◽

Electrorheological Fluids ◽

Flow Curves ◽

Homogeneous Solutions ◽

Electrorheological Effect ◽

Active Liquid ◽

Er Fluids ◽

Crystalline Matrix

Hybrid electrorheological fluids comprising powdered conjugated polymers dispersed in solutions of a liquid crystalline polymer were prepared and studied. FeCl 3 doped poly(p-phenylene) and pyrolised polyacrylonitrile were chosen as the dispersed phase and poly(n-hexyl isocyanate) dissolved in xylene was used as the active liquid matrix. All the component materials were extensively characterized by various methods. Flow curves of the hybrid ER fluids were recorded under electric field and compared with analogous curves obtained for dispersions of the powders in silicone oil and with homogeneous solutions of the LC polymer in xylene. A very significant enhancement of the ER effect in the studied hybrid fluids was observed.

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Graphene Oxide and Its Inorganic Composites: Fabrication and Electrorheological Response

Materials ◽

10.3390/ma12132185 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2185 ◽

Cited By ~ 3

Author(s):

Dong ◽

Kim ◽

Choi

Keyword(s):

Graphene Oxide ◽

Review Paper ◽

Inorganic Materials ◽

Flow Curves ◽

Dielectric Characteristics ◽

Oscillation Analysis ◽

Inorganic Composites ◽

Steady Shear Flow ◽

Dynamic Yield ◽

Er Fluids

Composite particles associated with graphene oxide (GO) and inorganic materials provide the synergistic properties of an appropriate electrical conductivity of GO with the good dielectric characteristics of inorganic materials, making them attractive candidates for electrorheological (ER) materials. This review paper focuses on the fabrication mechanisms of GO/inorganic composites and their ER response when suspended in a non-conducting medium, including steady shear flow curves, dynamic yield stress, On-Off tests, and dynamic oscillation analysis. Furthermore, the morphologies of these composites, dielectric properties, and sedimentation of the ER fluids are covered.

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Hysteresis Behaviors of Poly (Naphthalene Quinone) Radical Electrorheological Fluid

International Journal of Modern Physics B ◽

10.1142/s0217979299001946 ◽

1999 ◽

Vol 13 (14n16) ◽

pp. 1901-1907 ◽

Cited By ~ 27

Author(s):

Hyoung J. Choi ◽

Min S. Cho ◽

Myung S. Jhon

Keyword(s):

Shear Rate ◽

Silicone Oil ◽

Electrorheological Fluid ◽

Shear Stresses ◽

Hysteresis Phenomenon ◽

Rate Region ◽

Er Fluids ◽

High Voltage Generator ◽

Er Fluid ◽

Low Shear

As a potential electrorheological(ER) material, poly(naphthalene quinone) radical (PNQR) ER fluid was prepared, and its rheological behavior and hysteresis phenomenon were investigated. PNQR was synthesized by Friedel-Crafts acylation between naphthalene and phthalic anhydride, using zinc chloride as a catalyst at 256°C. A Physica rheometer equipped with a high voltage generator was used to measure the rheological properties of the ER fluids, which were prepared by dispersing PNQR in silicone oil at several particle concentrations. Shear stresses were observed to decrease as shear rate increased in the region of slow deformation rate. It was further found that ER fluid showed different hysteresis behaviors according to the shear rate ranges; thixotropy was observed in the low shear rate region (0.007-0.51/s) and anti-thixotropy in the high shear rate region (0.5-10001/s). Controlled shear stress mode was also applied to observe similar behaviors.

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Numerical Simulation on Dynamics and Thermal Decomposition of Spallation Polymer Particles Flying in Polymer Ablated Arcs

IEEJ Transactions on Power and Energy ◽

10.1541/ieejpes.135.681 ◽

2015 ◽

Vol 135 (11) ◽

pp. 681-687 ◽

Cited By ~ 2

Author(s):

Takuya Nakagawa ◽

Tomoyuki Nakano ◽

Yasunori Tanaka ◽

Yoshihiko Uesugi ◽

Tatsuo Ishijima

Keyword(s):

Numerical Simulation ◽

Thermal Decomposition ◽

Polymer Particles

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RELAÇÃO VAZÃO x PRESSÃO EM MICROASPERSORES DAN 2001 SOB CONDIÇÃO ADVERSA DE OPERAÇÃO

Irriga ◽

10.15809/irriga.2003v8n1p63-68 ◽

2003 ◽

Vol 8 (1) ◽

pp. 63-68 ◽

Cited By ~ 1

Author(s):

Marco Antonio Fonseca Conceição ◽

Rubens Duarte Coelho

Keyword(s):

Hydraulic Performance ◽

Sao Paulo ◽

The Self ◽

São Paulo ◽

Flow Curves ◽

Pressure Flow ◽

Adverse Condition ◽

Irrigation Time ◽

E Mail ◽

Stable Flow

RELAÇÃO VAZÃO x PRESSÃO EM MICROASPERSORES DAN 2001 SOB CONDIÇÃO ADVERSA DE OPERAÇÃO Marco Antônio Fonseca ConceiçãoEmbrapa Uva e Vinho, Estação Experimental de Jales, Jales, SP. CP 241. CEP 15700-000.E-mail: [email protected] Duarte CoelhoDepartamento de Engenharia Rural, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo, Piracicaba, SP. CP 09, CEP 13418-900.E-mail: [email protected] 1 RESUMO Alguns microaspersores possuem membranas que regulam a sua pressão de operação, mantendo a vazão praticamente estável dentro de uma faixa de pressão na rede hidráulica. Operadores de irrigação no campo, muitas vezes com baixo nível de instrução e sem orientação profissional qualificada, visando reduzir problemas de entupimento ou para diminuir o tempo de irrigação, costumam retirar as membranas autocompensantes para aumentar a vazão do emissores, o que pode comprometer o desempenho hidráulico do sistema. Para avaliar o efeito da retirada da membrana sobre as vazões dos microaspersores, no presente trabalho determinou-se as relações entre pressão e vazão para sete bocais do microaspersor DAN 2001, operando na ausência da membrana autocompensante. As curvas pressão-vazão sem as membranas autocompensantes apresentaram comportamento potencial com expoentes variando entre 0,58 e 0,64. As vazões dos microaspersores sem as membranas aumentaram de forma inversamente proporcional aos diâmetros dos emissores, quando comparadas às vazões nominais com as membranas. UNITERMOS: Hidráulica, irrigação, microaspersão. CONCEIÇÃO, M.A.F.; COELHO, R.D. FLOW X PRESSURE RELATIONSHIP FOR DAN 2001 MICROSPRINKLERS UNDER ADVERSE CONDITION 2 ABSTRACT Many types of microsprinklers have a self-compensating membrane to regulate their pressure, keeping a stable flow. Many producers usually take the membranes off to reduce clogging problems or irrigation time. This procedure could endanger the system hydraulic performance. To evaluate the effect of taking off the self-compensating membrane from microsprinklers it was determined, in the present work, the pressure-flow relationship for seven Dan 2001 microsprinkler nozzles operating without the membrane. The pressure-flow curves presented a potential behavior with the exponents varying from 0.58 to 0.64. Microsprinkler flows without the membranes increased inversely proportional to the emitter diameters, comparing to the nominal flows using the membranes. KEYWORDS: Hydraulic, irrigation, microsprinkler.

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