Simulations of the Motion of Colloidal Particles in Alternating Electric Fields

1994 ◽  
Vol 8 (5) ◽  
pp. 524
Author(s):  
Yue Hu
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Alternating Electric Fields

Particle Compaction with Alternating Electric Fields: The Effects of Electrode Geometry

1986 ◽  
Vol 73 ◽  
Author(s):  
Alan J. Hurd
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Dielectric Material ◽  
Double Layers ◽  
Electrode Geometry ◽  
Dipole Interactions ◽  
Alternating Electric Fields ◽  
Alternating Electric Field ◽  
Dc Bias ◽  
Induced Dipoles

ABSTRACTA technique for inducing ordered, close-packed arrangements of various symmetries among colloidal particles is discussed. An external alternating electric field applied to the colloid induces dipole interactions of variable strength by polarizing either the dielectric material of the particles or their electrostatic double layers. Ordering in various symmetries can be obtained by switching the field rapidly between pairs of electrodes, thereby changing the orientation of the induced dipoles. A small dc bias serves to deposit and compact the aligned particles.

Electro-optic observations of electrodynamic band formation in colloidal suspensions

1990 ◽  
Vol 427 (1873) ◽  
pp. 321-330 ◽  
Keyword(s):  
Electric Fields ◽  
Colloidal Particles ◽  
Local Density ◽  
Low Frequency ◽  
Colloidal Suspensions ◽  
Field Vector ◽  
High Concentration ◽  
Band Formation ◽  
Alternating Electric Fields ◽  
Field Lines

In static and low-frequency electric fields, colloidal particles in suspension tend to associate into ‘strings’ or ‘pearl chains’ along the field lines. A phenomenon has been observed in which, under long duration alternating electric fields, colloidal particles in aqueous or conducting media exhibit an electrodynamic instability in which they gather into high concentration ‘bands’ which run essentially perpendicular to the applied field vector. A detailed study is catalogued herein for aqueous suspensions of the discotic mineral kaolinite. A theory has been developed, which embraces the ‘pearl chain’ and ‘band’ formations, demonstrating that one can be formed from the other with increasing frequency and field strength and illustrating the dependence of band formation on electrophoretic mobility as observed in related electro-optical experiments. The value of the phenomenon as a mechanism for concentrating dispersed colloidal particles into regions of very high local density is apparent.

Standing Excitation Waves in the Heart Induced by Strong Alternating Electric Fields

2001 ◽  
Vol 87 (16) ◽  
Author(s):  
Richard A. Gray ◽  
Oleg A. Mornev ◽  
José Jalife ◽  
Oleg V. Aslanidi ◽  
Arkady M. Pertsov
Keyword(s):  
Electric Fields ◽  
Alternating Electric Fields

scholarly journals Water-Tree Resistant Characteristics of Crosslinker-Modified-SiO2/XLPE Nanocomposites

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1398
Author(s):  
Yong-Qi Zhang ◽  
Xuan Wang ◽  
Ping-Lan Yu ◽  
Wei-Feng Sun
Keyword(s):  
Electric Fields ◽  
Tree Growth ◽  
Mechanical Analysis ◽  
Water Molecules ◽  
Crosslinking Degree ◽  
Water Tree ◽  
Tree Resistance ◽  
Alternating Electric Fields ◽  
Trimethylolpropane Triacrylate ◽  
Mechanical Performances

Trimethylolpropane triacrylate (TMPTA) as a photoactive crosslinker is grafted onto hydrophobic nanosilica surface through click chemical reactions of mercapto double bonds to prepare the functionalized nanoparticles (TMPTA-s-SiO2), which are used to develop TMPTA-s-SiO2/XLPE nanocomposites with improvements in mechanical strength and electrical resistance. The expedited aging experiments of water-tree growth are performed with a water-knife electrode and analyzed in consistence with the mechanical performances evaluated by means of dynamic thermo-mechanical analysis (DMA) and tensile stress–strain characteristics. Due to the dense cross-linking network of polyethylene molecular chains formed on the TMPTA-modified surfaces of SiO2 nanofillers, TMPTA-s-SiO2 nanofillers are chemically introduced into XLPE matrix to acquire higher crosslinking degree and connection strength in the amorphous regions between polyethylene lamellae, accounting for the higher water-tree resistance and ameliorated mechanical performances, compared with pure XLPE and neat-SiO2/XLPE nanocomposite. Hydrophilic TMPTA molecules grafted on the nano-SiO2 surface can inhibit the condensation of water molecules into water micro-beads at insulation defects, thus attenuating the damage of water micro-beads to polyethylene configurations under alternating electric fields and thus restricting water-tree growth in amorphous regions. The intensified interfaces between TMPTA-s-SiO2 nanofillers and XLPE matrix limit the segment motions of polyethylene molecular chains and resist the diffusion of water molecules in XLPE amorphous regions, which further contributes to the excellent water-tree resistance of TMPTA-s-SiO2/XLPE nanocomposites.

scholarly journals Establishment of a New Device for Electrical Stimulation of Non-Degenerative Cartilage Cells In Vitro

2021 ◽  
Vol 22 (1) ◽  
pp. 394
Author(s):  
Simone Krueger ◽  
Alexander Riess ◽  
Anika Jonitz-Heincke ◽  
Alina Weizel ◽  
Anika Seyfarth ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Cartilage Tissue ◽  
Type I ◽  
Dependent Manner ◽  
New Device ◽  
Alternating Electric Fields ◽  
Cartilage Cells ◽  
Stimulation Of

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.

Water film motor driven by alternating electric fields: Its dynamical characteristics

2012 ◽  
Vol 85 (3) ◽  
Author(s):  
Zhong-Qiang Liu ◽  
Guang-Cai Zhang ◽  
Ying-Jun Li ◽  
Su-Rong Jiang
Keyword(s):  
Electric Fields ◽  
Water Film ◽  
Dynamical Characteristics ◽  
Alternating Electric Fields

Comment on “Mechanism for Alternating Electric Fields Induced-Effects on Cytosolic Calcium"

2010 ◽  
Vol 27 (4) ◽  
pp. 049901
Author(s):  
Dimitris J Panagopoulos ◽  
Andreas Karabarbounis ◽  
Lukas H Margaritis
Keyword(s):  
Electric Fields ◽  
Cytosolic Calcium ◽  
Alternating Electric Fields

Photorefractive Materials

MRS Bulletin ◽  
1994 ◽  
Vol 19 (3) ◽  
pp. 29-31 ◽  
Author(s):  
F. Agulló-López
Keyword(s):  
Electric Fields ◽  
Communication Technologies ◽  
Third Order ◽  
Nonlinear Materials ◽  
Light Pattern ◽  
Alternating Electric Fields ◽  
Beam Coupling ◽  
Photorefractive Materials ◽  
A Charge ◽  
Electrooptic Devices

There is a growing demand for nonlinear optical materials for a variety of applications—lasers and coherent sources, electrooptic devices, communication technologies, and optical processors and computers. Nonlinear optics is a vast field requiring materials with diverse performance features. Photorefractive (PR) materials, which experience a change in the refractive index under the effect of inhomogeneous illumination, constitute a relevant branch of the field. They behave as third-order nonlinear materials, which can be considered, in general, as photorefractive. However, the materials more commonly designated as photorefractives involve a charge-transport-induced nonlinearity, and it is these materials which are the object of this issue of the MRS Bulletin.At variance with conventional (often designated as Kerr) nonlinear materials, photorefractives are sensitive not to the local light intensity but to its spatial variation; i.e., they are nonlocal materials. This feature makes them more complicated to deal with than their conventional counterparts, since a χ(3) susceptibility cannot be properly defined (except as a k-dependent function). On the other hand, this sensitivity gives them some unique and interesting features. In particular, an interference light pattern illuminating the crystal and the generated index grating are phase-shifted, leading to remarkable beam coupling and amplification effects. The coupling gain can be markedly enhanced by applying alternating electric fields or by oscillating the interference fringes with a piezoelectric mirror. Efficient image amplifiers have been made using this effect.

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