Multiple correlation between auroral and magnetic pulsations: 2. Determination of electric currents and electric fields around a pulsating auroral patch

Abstract In this paper, I review some of our work on the use of magneto hydrodynamics (MHD) for pumping, controlling, and stirring fluids in microdevices. In many applications, one operates with liquids that are at least slightly conductive such as biological fluids. By patterning electrodes inside flow conduits and subjecting these electrodes to potential differences, one can induce electric currents in the liquid. In the presence of a magnetic field, a Lorentz force is generated in a direction that is perpendicular to both the magnetic and electric fields. Since one has a great amount of freedom in patterning the electrodes, one can induce forces in various directions so as to generate complex flows including “guided” flows in virtual, wall-less channels. The magnetic flux generators can be either embedded in the device or be external. Despite their unfavorable scaling (the magnitude of the forces is proportional to the fluid volume), MHD offers many advantages such as the flexibility of applying forces in any desired direction and the ability to adjust the magnitude of the forces by adjusting either the electric and/or magnetic fields. We provide examples of (i) MHD pumps; (ii) controlled networks of conduits in which each conduit is equipped with a MHD actuator and by controlling the voltage applied to each actuator, one can direct the liquid to flow in any desired way without a need for valves; and (iii) MHD stirrers including stirrers that exhibit chaotic advection.

Download Full-text

Experimental Determination of the Electrostatic Contribution to the Crystalline Electric Fields in Non-Cubic Metals

Crystalline Electric Field Effects in f-Electron Magnetism ◽

10.1007/978-1-4684-8646-9_52 ◽

1982 ◽

pp. 461-466 ◽

Cited By ~ 2

Author(s):

R. A. B. Devine ◽

Y. Berthier

Keyword(s):

Experimental Determination ◽

Electric Fields ◽

Cubic Metals ◽

Electrostatic Contribution ◽

Crystalline Electric Fields

Download Full-text

Determination of the Internal Electric Field in the Electrooptic Active Layer of Multilayer Polymer Stacks

MRS Proceedings ◽

10.1557/proc-488-413 ◽

1997 ◽

Vol 488 ◽

Author(s):

S. Grossmann ◽

T. Weyrauch ◽

W. Haase

Keyword(s):

Electric Field ◽

Electric Fields ◽

Time Dependent ◽

Polymer Interfaces ◽

Internal Electric Field ◽

Inhomogeneous Distribution ◽

Time Dependent Behaviour ◽

Dependent Behaviour

AbstractWe report on a method to investigate the inhomogeneous distribution of an electric dc field in multilayer polymer stacks. In situ electroabsorption (EA) measurements are applied in order to estimate the local electric fields in double layer polymer films. The observed time dependent behaviour is compared with a model equivalent circuit. The results indicate that besides the relation of ohmic resistivities and capacities of the different polymer layers in the investigated systems also the influence of the electric properties of polymer/electrode and polymer/polymer interfaces must be considered.

Download Full-text

A III B VI PHOTOVOLTAIC RECEPTORS FOR EXPERIMENTAL DETERMINATION OF CARBON COMPOUNDS IN ATMOSPHERE

Journal of Engineering Studies and Research ◽

10.29081/jesr.v19i3.111 ◽

2016 ◽

Vol 19 (3) ◽

Author(s):

IULIANA CARAMAN ◽

IGOR EVTODIEV ◽

OXANA RACOVEŢ ◽

MARIUS STAMATE

Keyword(s):

Electric Fields ◽

Full Range ◽

Absorption Bands ◽

Gaseous State ◽

Wide Range ◽

Carbon Compounds ◽

Strong Electric Fields ◽

Qualitative Measurements ◽

Semiconductor Type

This paper examines the prospects of using semiconductor layered A III B VI type - photovoltaic cells and the photoresistors as receptors for quantitative and qualitative measurements of carbon oxides. Carbon compounds in gaseous state form absorption bands of electromagnetic radiation in a wide range of spectrum (200 ÷ 100 000) cm-1. The light absorbed or emitted in these bands at the excitations with ionizing radiation (X, γ) or strong electric fields contain direct information about the concentration of these molecules. The frequencies that correspond to maxima of these bands are characteristic parameters of absorbing molecules. Fundamental absorption bands of CO, CO 2 and NC have the edge of band at the border of ultraviolet-vacuum, while the emission bands d cover their full range of wave numbers from 45000 cm-1 to 10000 cm-1. Two types of radiation receptors from lamellar semiconductor type AIIIBVI photosensitive in this spectral range are studied.

Download Full-text

TEMPERATURE DEPENDENCE OF ELECTRICAL RESISTANCE OF INDIVIDUAL CARBON NANOTUBES AND CARBON NANOTUBES NETWORK

Modern Physics Letters B ◽

10.1142/s0217984912501369 ◽

2012 ◽

Vol 26 (21) ◽

pp. 1250136 ◽

Cited By ~ 18

Author(s):

SAJJAD DEHGHANI ◽

MOHAMMAD KAZEM MORAVVEJ-FARSHI ◽

MOHAMMAD HOSSEIN SHEIKHI

Keyword(s):

Carbon Nanotubes ◽

Temperature Dependence ◽

Electric Fields ◽

Electrical Resistance ◽

Electrode Materials ◽

Effect Of Temperature ◽

Electrode Spacing ◽

Single Wall Carbon Nanotubes ◽

Tube Metal

We present a model to understand the effect of temperature on the electrical resistance of individual semiconducting single wall carbon nanotubes (s-SWCNTs) of various diameters under various electric fields. The temperature dependence of the resistance of s-SWCNTs and metallic SWCNTs (m-SWCNTs) are compared. These results help us to understand the temperature dependence of the resistance of SWCNTs network. We experimentally examine the temperature dependence of the resistance of random networks of SWCNTs, prepared by dispersing CNTs in ethanol and drop-casting the solution on prefabricated metallic electrodes. Examining various samples with different electrode materials and spacings, we find that the dominant resistance in determination of the temperature dependence of resistance of the network is the resistance of individual tubes, rather than the tube–tube resistance or tube–metal contact resistance. It is also found that the tube–tube resistance depends on the electrode spacing and it is more important for larger electrode spacings. By applying high electric field to burn the all-metallic paths of the SWCNTs network, the temperature dependence of the resistance of s-SWCNTs is also examined. We also investigate the effect of acid treatment of CNTs on the temperature dependence of the resistance of SWCNTs and also multi-wall CNTs (MWCNTs) networks.

Download Full-text

Determination of the Mobile-Hydrogen Charge State in Hydrogenated Amorphous Silicon

MRS Proceedings ◽

10.1557/proc-664-a28.2 ◽

2001 ◽

Vol 664 ◽

Author(s):

Brent P. Nelsona ◽

Yueqin Xu ◽

Robert C. Reedy ◽

Richard S. Crandall ◽

A. Harv Mahan ◽

...

Keyword(s):

Amorphous Silicon ◽

Electric Fields ◽

Correlation Energy ◽

Hydrogen Charge ◽

Hydrogenated Amorphous Silicon ◽

Mobile Hydrogen ◽

Almost All ◽

Hydrogenated Amorphous ◽

Best Fit

ABSTRACTWe find that hydrogen diffuses as H+, H0, or H- in hydrogenated amorphous silicon depending on its location within the i-layer of a p-i-n device. We annealed a set of five p-i-n devices, each with a thin deuterium-doped layer at a different location in the i-layer, and observed the D-diffusion using secondary ionmass spectrometry (SIMS). When H-diffuses in a charged state, electric fields in the device strongly influence the direction and distance of diffusion. When D is incorporated into a device near the p-layer, almost all of the D-diffusion occurs as D+, and when the D is incorporated near the n-layer, most of the D-diffusion occurs as D-. We correlate the preferential direction of D-motion at given depth within the i-layer, with the local Fermi level (as calculated by solar cell simulations), to empirically determine an effective correlation energy for mobile-H electronic transitions of 0.39 ± 0.1 eV. Using this procedure, the best fit to the data produces a disorder broadening of the transition levels of ∼0.25 eV. The midpoint between the H0/+ and the H0/- transition levels is ∼0.20 ± 0.05 eV above midgap.

Download Full-text