Steady-state deformation of a vesicle in alternating electric fields

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.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22010394 ◽

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.

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

Physical Review E ◽

10.1103/physreve.85.036314 ◽

2012 ◽

Vol 85 (3) ◽

Cited By ~ 9

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

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Numerical study of electric field effects on the deformation of two-dimensional liquid drops in simple shear flow at arbitrary Reynolds number

Journal of Fluid Mechanics ◽

10.1017/s0022112009006442 ◽

2009 ◽

Vol 626 ◽

pp. 367-393 ◽

Cited By ~ 32

Author(s):

STEFAN MÄHLMANN ◽

DEMETRIOS T. PAPAGEORGIOU

Keyword(s):

Steady State ◽

Shear Flow ◽

Electric Field ◽

Electric Fields ◽

Simple Shear ◽

Simple Shear Flow ◽

Physical Parameters ◽

Shear Stresses ◽

Two Dimensional ◽

Liquid Drops

The effect of an electric field on a periodic array of two-dimensional liquid drops suspended in simple shear flow is studied numerically. The shear is produced by moving the parallel walls of the channel containing the fluids at equal speeds but in opposite directions and an electric field is generated by imposing a constant voltage difference across the channel walls. The level set method is adapted to electrohydrodynamics problems that include a background flow in order to compute the effects of permittivity and conductivity differences between the two phases on the dynamics and drop configurations. The electric field introduces additional interfacial stresses at the drop interface and we perform extensive computations to assess the combined effects of electric fields, surface tension and inertia. Our computations for perfect dielectric systems indicate that the electric field increases the drop deformation to generate elongated drops at steady state, and at the same time alters the drop orientation by increasing alignment with the vertical, which is the direction of the underlying electric field. These phenomena are observed for a range of values of Reynolds and capillary numbers. Computations using the leaky dielectric model also indicate that for certain combinations of electric properties the drop can undergo enhanced alignment with the vertical or the horizontal, as compared to perfect dielectric systems. For cases of enhanced elongation and alignment with the vertical, the flow positions the droplets closer to the channel walls where they cause larger wall shear stresses. We also establish that a sufficiently strong electric field can be used to destabilize the flow in the sense that steady-state droplets that can exist in its absence for a set of physical parameters, become increasingly and indefinitely elongated until additional mechanisms can lead to rupture. It is suggested that electric fields can be used to enhance such phenomena.

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Effect of alternating electric fields on the behaviour of small-scale laminar diffusion flames

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2015.06.041 ◽

2015 ◽

Vol 89 ◽

pp. 306-315 ◽

Cited By ~ 31

Author(s):

Yunhua Gan ◽

Yanlai Luo ◽

Mei Wang ◽

Yanling Shi ◽

Yuying Yan

Keyword(s):

Electric Fields ◽

Diffusion Flames ◽

Small Scale ◽

Laminar Diffusion Flames ◽

Alternating Electric Fields ◽

Laminar Diffusion

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

Chinese Physics Letters ◽

10.1088/0256-307x/27/4/049901 ◽

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

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Photorefractive Materials

MRS Bulletin ◽

10.1557/s0883769400039658 ◽

1994 ◽

Vol 19 (3) ◽

pp. 29-31 ◽

Cited By ~ 1

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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