scholarly journals Impact of electric field variability on Joule heating and thermospheric temperature and density

2009 ◽  
Vol 36 (8) ◽  
Author(s):  
Yue Deng ◽  
Astrid Maute ◽  
Arthur D. Richmond ◽  
Raymond G. Roble
Keyword(s):  
Electric Field ◽  
Joule Heating ◽  
Field Variability

Joule Heating Induced Temperature Gradient Focusing for Microfluidic Concentration of Samples

2010 ◽  
Author(s):  
Zhengwei Ge ◽  
Chun Yang
Keyword(s):  
Temperature Gradient ◽  
Electric Field ◽  
Joule Heating ◽  
Field Experiments ◽  
Dc Voltage ◽  
Sample Concentration ◽  
Great Achievement ◽  
Temperature Gradient Focusing ◽  
Concentration Enhancement ◽  
High Frequency Ac

Microfluidic concentration of sample species is achieved using the temperature gradient focusing (TGF) in a microchannel with a step change in the cross-section under a pure direct current (DC) field or a combined alternating current (AC) and DC electric field. Experiments were carried out to study the effects of applied voltage, buffer concentration and channel size on sample concentration in the TGF processes. These effects were analyzed and summarized using a dimensionless Joule number that is introduced in this study. In addition, Joule number effect in the Poly-dimethylsiloxane (PDMS)/PDMS microdevice was compared with the PDMS/Glass microdevice. A more than 450-fold concentration enhancement was obtained within 75 seconds in the PDMS/PDMS microdevice. Results also showed that the high frequency AC electric field which contributes to produce the temperature gradient and reduces the required DC voltage for the sample concentration. The lower DC voltage has generated slower electroosmotic flow (EOF), which reduces the backpressure effect associated with the finite reservoir size. Finally, a more than 2500-fold concentration enhancement was obtained within 14 minutes in the PDMS/PDMS microdevice, which was a great achievement in this TGF technique using inherent Joule heating effects.

Electric field variability associated with the Millstone Hill electric field model

2000 ◽  
Vol 105 (A3) ◽  
pp. 5265-5273 ◽  
Author(s):  
M. V. Codrescu ◽  
T. J. Fuller-Rowell ◽  
J. C. Foster ◽  
J. M. Holt ◽  
S. J. Cariglia
Keyword(s):  
Electric Field ◽  
Field Model ◽  
Field Variability

scholarly journals Integrating electric field modelling and neuroimaging to explain inter-individual variability of tACS effects

2019 ◽  
Author(s):  
Florian H. Kasten ◽  
Katharina Duecker ◽  
Marike C. Maack ◽  
Arnd Meiser ◽  
Christoph S. Herrmann
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Individual Variability ◽  
Transcranial Electrical Stimulation ◽  
Field Modelling ◽  
Novel Approach ◽  
Before And After ◽  
Transcranial Alternating Current Stimulation ◽  
The Brain ◽  
Field Variability

AbstractUnderstanding variability of transcranial electrical stimulation (tES) effects is one of the major challenges in the brain stimulation community. Promising candidates to explain this variability are individual anatomy and the resulting differences of electric fields inside the brain. We integrated individual simulations of electric fields during tES with source-localization to predict variability of transcranial alternating current stimulation (tACS) aftereffects on α-oscillations. In two experiments, participants received 20 minutes of either α-tACS (1 mA) or sham stimulation. Magnetoencephalogram was recorded for 10 minutes before and after stimulation. tACS caused a larger power increase in the α-band as compared to sham. The variability of this effect was significantly predicted by measures derived from individual electric field modelling. Our results directly link electric field variability to variability of tACS outcomes, stressing the importance of individualizing stimulation protocols and providing a novel approach to analyze tACS effects in terms of dose-response relationships.

3D Numerical Analysis of Joule Heating Effect on Electroosmotic Flow in Microchannels

2006 ◽  
Author(s):  
Reza Monazami ◽  
Shahrzad Yazdi ◽  
Mahmoud A. Salehi
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Charge Distribution ◽  
Cross Section ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Three Dimensional ◽  
Micro Channel ◽  
Heating Effect ◽  
Energy Equations

In this paper, a three-dimensional numerical model is developed to analyze the influence of the Joule heating on flow characteristics of an electroosmotic flow through square cross section micro-channels. The governing system of equations consists of three sets of equations: electric potential distribution, flow-field and energy equations. The solution procedure involves three steps. The net charge distribution on the cross section of the micro-channel is computed by solving two-dimensional Poisson-Boltzmann equation using the finite element method. Then, using the computed fluid’s charge distribution, the magnitude of the resulting body force due to interaction of an external electric field with the charged fluid elements is calculated along the micro-channel. Finally, three dimensional coupled Navier-Stokes and energy equations are solved by considering the presence of the electro-kinetic body forces and the volumetric heat generation due to Joule heating for three different external electric field strengths. The results reveal that flow patterns are significantly affected by temperature field distribution caused by Joule heating effect especially for high electric field strength cases.

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