scholarly journals Electric field induced gelation in aqueous nanoclay suspensions

Soft Matter ◽  
2018 ◽  
Vol 14 (34) ◽  
pp. 6974-6982 ◽  
Author(s):  
Paramesh Gadige ◽  
Ranjini Bandyopadhyay
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Soft Solids ◽  
Clay Suspensions ◽  
Dc Electric Fields

Liquid-like aqueous colloidal LAPONITE® clay suspensions rapidly transform into soft solids due to the application of DC electric fields.

Pulsed DC electric fields couple to natural NAD(P)H oscillations in HT-1080 fibrosarcoma cells

2001 ◽  
Vol 114 (8) ◽  
pp. 1515-1520 ◽  
Author(s):  
A.J. Rosenspire ◽  
A.L. Kindzelskii ◽  
H.R. Petty
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cell Function ◽  
Low Frequency ◽  
Reactive Oxygen Metabolites ◽  
Pulsed Dc ◽  
Fibrosarcoma Cells ◽  
Chemotactic Factors ◽  
Oxygen Metabolites ◽  
Dc Electric Fields

Previously, we have demonstrated that NAD(P)H levels in neutrophils and macrophages are oscillatory. We have also found that weak ultra low frequency AC or pulsed DC electric fields can resonate with, and increase the amplitude of, NAD(P)H oscillations in these cells. For these cells, increased NAD(P)H amplitudes directly signal changes in behavior in the absence of cytokines or chemotactic factors. Here, we have studied the effect of pulsed DC electric fields on HT-1080 fibrosarcoma cells. As in neutrophils and macrophages, NAD(P)H levels oscillate. We find that weak (~10(-)(5) V/m), but properly phased DC (pulsed) electric fields, resonate with NAD(P)H oscillations in polarized and migratory, but not spherical, HT-1080 cells. In this instance, electric field resonance signals an increase in HT-1080 pericellular proteolytic activity. Electric field resonance also triggers an immediate increase in the production of reactive oxygen metabolites. Under resonance conditions, we find evidence of DNA damage in HT-1080 cells in as little as 5 minutes. Thus the ability of external electric fields to effect cell function and physiology by acting on NAD(P)H oscillations is not restricted to cells of the hematopoietic lineage, but may be a universal property of many, if not all polarized and migratory eukaryotic cells.

Effects of DC electric fields on neuronal excitability: A bifurcation analysis

2014 ◽  
Vol 28 (18) ◽  
pp. 1450114 ◽  
Author(s):  
Yanqiu Che ◽  
Huiyan Li ◽  
Chunxiao Han ◽  
Xile Wei ◽  
Bin Deng ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Parameter Space ◽  
Bifurcation Analysis ◽  
Neural Control ◽  
Neuronal Excitability ◽  
Modulation Method ◽  
Two Dimensional ◽  
Dimensional Parameter ◽  
Dc Electric Fields

In this paper, the effects of external DC electric fields on the neuro-computational properties are investigated in the context of Morris–Lecar (ML) model with bifurcation analysis. We obtain the detailed bifurcation diagram in two-dimensional parameter space of externally applied DC current and trans-membrane potential induced by external DC electric field. The bifurcation sets partition the two-dimensional parameter space in terms of the qualitatively different behaviors of the ML model. Thus the neuron's information encodes the stimulus information, and vice versa, which is significant in neural control. Furthermore, we identify the electric field as a key parameter to control the transitions among four different excitability and spiking properties, which facilitates the design of electric fields based neuronal modulation method.

Deformation of Nitrogen Bubbles in DC Electric Fields

2006 ◽  
Author(s):  
Feng Chen ◽  
Yao Peng ◽  
Yaozu Song ◽  
Min Chen
Keyword(s):  
Aspect Ratio ◽  
Electric Field ◽  
Electric Fields ◽  
Transformer Oil ◽  
Working Fluid ◽  
Direction Parallel ◽  
Electric Field Magnitude ◽  
Field Magnitude ◽  
Nitrogen Bubbles ◽  
Dc Electric Fields

The deformation of nitrogen bubbles in transformer oil with various DC electric fields was studied experimentally and theoretically. The bubble deformation was visualized by a high-speed digital camera. The major axis of the bubble was elongated along the direction parallel to the applied electric field, with the elongation increasing as the electric field magnitude increased. The electrical Weber number (We) was used to correlate the electric field magnitude and the electric permittivity of the working fluid to the bubble aspect ratio (AR). The experimental results indicate that the bubble aspect ratio increases with increasing We. The total electrical stresses were calculated on an actual bubble shape including the electrostriction stresses.

Optical properties of nematic liquid crystal (C21H27NO2S) under AC/DC electric fields

2009 ◽  
Vol 87 (4) ◽  
pp. 293-298 ◽  
Author(s):  
Mehriban Emek ◽  
Nurettin Besli ◽  
Ahmet Yildirim ◽  
Suleyman Yilmaz
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Electric Field ◽  
Domain Structure ◽  
Nematic Liquid Crystal ◽  
Electric Fields ◽  
Transition Process ◽  
Optical Methods ◽  
Rotational Angle ◽  
Dc Electric Fields

In this study, the effects of the phase transition on the optical transmittance of the nematic liquid crystal C21H27NO2S, 4′-isothiocyanatophenyl-4-pentylbicyclo[2,2,2]octane-1-carboxylate are investigated in terms of temperature variation and rotational angle of the polarizer through electro-optical methods under AC / DC electric fields. It is observed that the domain structure of the material is affected considerably by the applied electric field as the temperature changes. Under applied electric fields, the crystal-nematic (CN) phase-transition point changes and the behaviour of the liquid crystal in the phase-transition region shows some differences. The intensity of the light passing through the system under a DC electric field increases as the electric field rises. Nevertheless, the intensity of the transmitted light under an AC electric field increases at the beginning and then decreases as the electric field rises to a temperature of more than 355 K. These results can be explained through the formation of a domain structure during the phase-transition process and the light scattering caused by these structures.

scholarly journals Electrical Property of Polypropylene Films Subjected to Different Temperatures and DC Electric Fields

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2956
Author(s):  
Chuyan Zhang ◽  
Weichen Shi ◽  
Qiao Wang ◽  
Mingguang Diao ◽  
Huseyin R. Hiziroglu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Elevated Temperatures ◽  
Dielectric Material ◽  
Effect Of Temperature ◽  
Uniform Electric Field ◽  
Time To Failure ◽  
Natural Clay ◽  
Nano Clay ◽  
Dc Electric Fields

A polypropylene (PP) film is usually used as a dielectric material in capacitors as well as cables. However, PP films may degrade because of the combined effect of temperature and electric field. In an earlier study, plain PP films and PP films loaded with nano-metric natural clay were studied under sinusoidal (AC) electric fields at power frequency and temperatures above the ambient. To better understand the electrical characteristics of PP film under various conditions, the objective of this study is to determine the time-to-breakdown of the plain PP and PP filled with 2% (wt) natural nano-clay when subjected to time-invariant (DC) electric fields at elevated temperatures. In order to achieve this objective, the effects of uniform as well as non-uniform electric fields were compared at the same temperature for the PP film. In this study, experimental results indicated that the time-to-breakdown of all PP films, plain or filled with nano-clay, decreases with the increase in electric field intensity, non-uniformity of the electric field, and temperature. It was also found that the time-to-breakdown of PP film filled with 2% (wt) natural nano-clay under DC electric field is longer and less sensitive to temperature. Furthermore, when compared with the results under the uniform electric field, PP film filled with 2% (wt) nano-metric natural clay indicates shorter time-to-failure under non-uniform DC electric fields. Finally, the morphology of the samples was observed by digital camera, optical micrography, and SEM, to better understand the mechanism of the breakdown.

Effects of AC/DC Electric Fields on Stretching DNA Molecules

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050065
Author(s):  
Ying Wang ◽  
Mingyan Gao ◽  
Yingmin Qu ◽  
Jun Hu ◽  
Ying Xie ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Dna Molecules ◽  
Dna Interactions ◽  
Biophysical Properties ◽  
Voltage Range ◽  
Atomic Force ◽  
Ac Electric Field ◽  
Dc Electric Field ◽  
Dc Electric Fields

The effects of AC/DC electric fields on stretching DNA molecules were discussed in this work. In the experiments of stretching DNA molecules with AC/DC electric fields, the voltage range was changed from 0[Formula: see text]V to 10[Formula: see text]V, and the frequency of AC electric field was kept at 50[Formula: see text]kHz. An atomic force microscope (AFM) was used to obtain DNA distributions under different electric fields. DNA molecules were curved and randomly distributed in solution if there was not any force applied to them. When an AC electric field was applied to the DNA sample, the curvature of DNA molecules was decreased gradually, and the stretching result was more obvious with the increase of voltage from 0.1[Formula: see text]V to 5[Formula: see text]V. The DNA molecules were broken when the voltage was increased to 6[Formula: see text]V. However, under the DC electric field, the stretching result of DNA molecules reached to their optimum state when the voltage was 2[Formula: see text]V, and they kept their steady state even though larger electric field intensities applied to the electrodes. The results can be used for the study of DNA–DNA, protein–DNA and quantum dot–DNA interactions and for the exploration of DNA biophysical properties.

scholarly journals Motility of cultured fish epidermal cells in the presence and absence of direct current electric fields.

1986 ◽  
Vol 102 (4) ◽  
pp. 1384-1399 ◽  
Author(s):  
M S Cooper ◽  
M Schliwa
Keyword(s):  
Membrane Potential ◽  
Electric Field ◽  
Electric Fields ◽  
Direct Current ◽  
Epidermal Cells ◽  
Resting Membrane Potential ◽  
Cell Clusters ◽  
Cell Locomotion ◽  
Presence And Absence ◽  
Dc Electric Fields

The motile behavior and cytoskeletal structures of fish epidermal cells (keratocytes) in the presence and absence of direct current (DC) electric fields were examined. These cells spontaneously show highly directional locomotion in culture, migrating at rates of up to 1 micron/s. When DC electric fields between 0.5 and 15 V/cm are applied, single epidermal cells as well as cell clusters and cell sheets migrate towards the cathode. Cell clusters and sheets break apart into single migratory cells in the upper range of these field strengths. Cell shape and morphology are unaltered when the keratocytes are guided by an electric field. Neither the spontaneous locomotion nor the electrically guided motility were found to be microtubule dependent. 1 mM La3+, 10 mM Co2+, 50 microM verapamil, and 50 microM nitrendipine (calcium channel antagonists) reversibly inhibited lamellipod formation and cell locomotion in both spontaneously migrating and electrically guided cells. Ciba-Geigy Product 28392, which stimulates the opening of calcium channels, and is a competitive inhibitor of nitrendipine, has no effect on the locomotion of keratocytes. Cell motility was also unaffected by hyperpolarizing and depolarizing (low and high K+) media. It is argued that while a tissue cell may accommodate changes in resting membrane potential without becoming more or less motile, the cell may not be able to counterbalance the effects of depolarization and hyperpolarization simultaneously. In this context, a gradient of membrane potential, which is induced by an external DC electric field, will serve as a persistent stimulus for cell locomotion.

Nonlinear Electrokinetic Transport Under Combined ac and dc Fields in Micro/Nanofluidic Interface Devices

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Vishal V. R. Nandigana ◽  
N. R. Aluru
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Concentration Polarization ◽  
Stokes Equations ◽  
Fluid Velocity ◽  
Navier Stokes ◽  
Electrokinetic Transport ◽  
Highly Nonlinear ◽  
Interface Devices ◽  
Dc Electric Fields

The integration of micro/nanofluidic devices led to many interesting phenomena and one of the most important and complex phenomenon among them is concentration polarization. In this paper, we report new physical insights in micro/nanofluidic interface devices on the application of ac and dc electric fields. By performing detailed numerical simulations based on the coupled Poisson, Nernst–Planck, and incompressible Navier–Stokes equations, we discuss electrokinetic transport and other hydrodynamic effects under the application of combined ac and dc electric fields for different nondimensional electrical double layer (EDL) thicknesses and nanochannel wall surface charge densities. We show that for a highly ion-selective nanochannel, the application of the combined ac/dc electric field, at amplitudes greater than the dc voltage and at a low Strouhal number, results in large dual concentration polarization regions (with unequal lengths) at both the micro/nanofluidic interfaces due to large and unequal voltage drops at these junctions. The highly nonlinear potential distribution gives rise to an electric field and body force that changes the electrokinetic fluid velocity from that obtained on the application of only a dc source.

scholarly journals Challenges when measuring the DC electric field very close to an insulator surface

2018 ◽  
Author(s):  
Birgitta Källstrand ◽  
Daniel Borg ◽  
Lars Walfridsson ◽  
Kenneth Johansson ◽  
Charles Doiron
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Spatial Resolution ◽  
Insulator Surface ◽  
Small Probe ◽  
Probe Size ◽  
Measurement Results ◽  
Excellent Spatial Resolution ◽  
Dc Electric Field ◽  
Dc Electric Fields

<p>A small probe that can measure DC electric fields in air has been developed. As a consequence of the probe size, it is possible to measure close to the surface of e.g. an HVDC insulator, and to resolve the field with an excellent spatial resolution. However, challenges have been identified when performing measurements close to a surface and its influence on the measurement results have been quantified. Measurement procedures have been developed to be able to correct for the possible net charging of the probe.</p>

DISSIPATIVE REGIME OF DYNAMIC LOCALIZATION IN DOUBLE QUANTUM DOT

2007 ◽  
Vol 06 (05) ◽  
pp. 389-393 ◽  
Author(s):  
VLADIMIR A. BURDOV ◽  
DMITRY SOLENOV
Keyword(s):  
Quantum Dot ◽  
Electric Field ◽  
Electric Fields ◽  
Double Quantum ◽  
Electron Dynamics ◽  
Dynamic Localization ◽  
Electron States ◽  
Double Quantum Dot ◽  
Dc Electric Fields

Dissipative electron dynamics in a double quantum dot, influenced by external ac and dc electric fields, has been analyzed. It was shown that the dissipation caused by phonon environment disappears under certain relations between electric field parameters. In this case one may perform the dynamic localization and form stable electron states localized within one of the dots.

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