Flexible Electrode Structures for Thermo-Tunneling Applications

2011 ◽  
Author(s):  
Eniko T. Enikov ◽  
Carlos Gamez ◽  
Shezaan Kanjiyani ◽  
Mahdi Ganji ◽  
Joshua Gill
Keyword(s):  
Magnetic Field ◽  
Contact Area ◽  
Numerical Solutions ◽  
Flexible Structures ◽  
Tunneling Current ◽  
Hot Electrons ◽  
Practical Implementation ◽  
Small Current ◽  
Thermo Electric ◽  
Asymmetric Mode

Combined thermionic emission and tunneling of hot electrons (thermo-tunneling) has emerged as a potential new solid-state cooling technology. Practical implementation of thermo-tunneling, however, requires the formation of a nanometer-sized gap spanning macroscopically significant surfaces. Thermo-tunneling of hot electrons across a few-nanometer gap has application to vacuum electronics, flat panel displays, and holds great potential in thermo-electric cooling and energy generation. Development of new thermo-tunneling applications requires creation of a stable nanometer gap between two surfaces. This presentation is focused on our effort to investigate the feasibility of creating such gaps using distributed electro-magnetic forces arising in thin-film flexible structures. Early efforts based on rigid electrodes showed that the effective tunneling approaches 400 square-micrometers, which albeit small, could lead to useful practical systems. In this presentation, we report a theoretical and experimental investigation of a thin-electrode system which could lead to further increase on the effective tunneling area. The device under study consists of a thin membrane collector electrode (anode) suspended over the emitting electrode (cathode). The structure is placed in a vacuum enclosure with an externally generated magnetic field perpendicular to the current flow in the membrane. The resulting Lorentz force is then directed upwards, separating the two surfaces. A mathematical model of the steady-state operation of the device is presented along with predictions of the contact area and tunneling current. Essential output parameters of the model include a central contact area measured by its length (delta) and the thermo-tunneling current. Both parameters are determined as a function of the externally applied external potential and magnetic field. Numerical solutions of the model show two possible operating modes: (1) symmetric deformation with negligibly small current; and (2) asymmetric mode where the B-field controls the current and contact area.

Numerical Simulation and Stability Analysis of Thin Flexible Micro Film for Thermotunneling Application

2012 ◽  
Author(s):  
Eniko T. Enikov ◽  
Mahdi Ganji
Keyword(s):  
Numerical Simulation ◽  
Contact Area ◽  
Numerical Solutions ◽  
Thermionic Emission ◽  
Hot Electrons ◽  
Beam Equation ◽  
Practical Implementation ◽  
Beam Model ◽  
Small Current ◽  
Thermo Electric

Combined thermionic emission and tunneling of hot electrons (thermo-tunneling) has emerged as a potential new solidstate cooling technology. Practical implementation of thermo-tunneling, however, requires the formation of a nanometer-sized gap spanning macroscopically significant surfaces. Thermo-tunneling is a term used to describe combined emission of hot electrons (thermionic emission) and tunneling of electrons through a narrow potential barrier between two surfaces (field emission). Thermo-tunneling of hot electrons across a few-nanometer gap has application to vacuum electronics, flat panel displays, and holds great potential in thermo-electric cooling and energy generation. Development of new thermo-tunneling applications requires creation of a stable nanometer gap between two surfaces. This presentation is focused on our effort to investigate the stability of the the thin flexible structure under electrostatic and lorenz forces opposing each other. In this presentation, we report the result of numerical simulation with some mathematical simplifications. The mathematical model used for the numerical simulation is well studied in the literature. Using forth-order partial differential beam equation, we studied the steady state solutions of the thermo-tunneling beam model using Galerkin method. Essential output parameters of the model include a central contact area measured by its length (delta) and the thermo-tunneling current. Both parameters are determined as a function of the externally applied external potential and magnetic field. Numerical solutions of the model show two possible operating modes: (1) symmetric deformation with negligibly small current; and (2) asymmetric mode where the B-field controls the current and contact area. Under practical values for the externally applied magnetic and electric fields, it has been shown that the second mode is only possible for electrode with very low work functions, e.g. below 0.5 eV. Therefore, novel materials such as Diamond-like carbon films are likely to be essential in thermo-tunneling applications.

Application of DQM Method to the Steady State Analysis of Thermo-Tunneling Electrodes

2013 ◽  
Author(s):  
Eniko T. Enikov ◽  
Mahdi Ganji
Keyword(s):  
Lorentz Force ◽  
Differential Quadrature Method ◽  
Tunneling Current ◽  
Hot Electrons ◽  
Flat Panel Displays ◽  
Thermo Electric ◽  
Vacuum Electronics ◽  
Combined Action ◽  
Non Local ◽  
The Stability

Thermo-tunneling of hot electrons across a few nanometer gap has application to vacuum electronics, flat panel displays, and holds great potential in thermo-electric cooling and energy generation. However development of such applications requires formation of dynamically balanced gap separating the two surfaces. One such approach is the use of Lorentz (repulsive) and Coulomb (attractive) forces to obtain an equilibrium gap between two elastic electrodes. The present paper describes the application of the Differential Quadrature Method (DQM) to the solution of a clamped-clamped Euler-Bernouli beam subject to the combined action of Lorentz and Coulomb forces. The results show that due to non-local action of the Lorentz force, the shape of the tunneling electrode is inherently non-uniform with Coulomb forces acting primarily at one end of the beam while the Lorentz force distributed along the remaining part. DQM method also allows analysis of the stability of the tunneling current as a function of the applied external potential and magnetic field. In addition to the classical electrostatic pull-in instability with no-tunneling, a second regime with non-zero tunneling current is also identified. To the best of our knowledge this is the first attempt to analyze this phenomenon under the effect of both Electrostatic and Lorenz forces in this particular case. Linear stability analysis of the tunneling regime indicates the appearance of a saddle-saddle bifurcation indicating unstable tunneling regime.

scholarly journals About the possibility of identification of hydrocarbon deposits with the help of NMR

2016 ◽  
Vol 5 (2) ◽  
pp. 551-559
Author(s):  
Pavlo M. Ivashchenko ◽  
Eduard A. Bakai ◽  
Alexander I. Yurchuk
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Absorption Spectra ◽  
Weak Magnetic Field ◽  
Directional Antennas ◽  
Practical Implementation ◽  
Practical Application ◽  
The Earth ◽  
Hydrocarbon Deposits

Abstract. The main purpose of this article is to review the theoretical prerequisites of nuclear magnetic resonance (NMR) application in tasks of search and exploration of hydrocarbon deposits. The identification peculiarities of hydrocarbon deposits in a weak magnetic field of the Earth were analysed. The necessity of using highly directional antennas for providing greater sounding depths as well as the use of absorption spectra of the sought-for minerals as sounding signals were identified and justified. A variant of practical implementation of such a system was examined and examples of practical application of the innovative NMR technology were provided.

scholarly journals Nonlinear force-free modeling of magnetic fields in flare-productive active regions

2015 ◽  
Vol 11 (S320) ◽  
pp. 167-174
Author(s):  
M. S. Wheatland ◽  
S. A. Gilchrist
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Boundary Data ◽  
Numerical Solutions ◽  
Free Field ◽  
Active Regions ◽  
Coronal Magnetic Field ◽  
Nonlinear Force ◽  
The Magnetic Field ◽  
Force Free Field

AbstractWe review nonlinear force-free field (NLFFF) modeling of magnetic fields in active regions. The NLFFF model (in which the electric current density is parallel to the magnetic field) is often adopted to describe the coronal magnetic field, and numerical solutions to the model are constructed based on photospheric vector magnetogram boundary data. Comparative tests of NLFFF codes on sets of boundary data have revealed significant problems, in particular associated with the inconsistency of the model and the data. Nevertheless NLFFF modeling is often applied, in particular to flare-productive active regions. We examine the results, and discuss their reliability.

scholarly journals The hall effect in liquid electrolytes

1913 ◽  
Vol 88 (606) ◽  
pp. 588-604 ◽  
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Electric Current ◽  
Metal Plate ◽  
Satisfactory Explanation ◽  
Thermo Electric ◽  
Field Independent ◽  
Set Up ◽  
The Magnetic Field ◽  
Thin Metal Plate

The distortion of the lines of flow of an electric current in a thin metal plate by the action of a magnetic field was discovered in 1879. Hall attributed this to the action of the magnetic field on the molecular currents in the metal film, which were deflected to one side or the other and accompanied by a corresponding twist of the equipotential lines. This explanation did not pass without criticism, and another theory of the effect found by Hall was published in 1884. In that paper the author seeks to explain the effect by assuming a combination of certain mechanical strains and Peltier effects, a thermo-electric current being set up between the strained and the unstrained portions. The effect of such strain was to produce a reverse effect in some metals, and these were precisely the metals for which the Hall effect was found to reverse. Aluminium was the only exception. In other respects, however, as shown by Hall in a later paper, Bidwell's theory did not stand the test of experiment, and the results lend no support to his theory, while they are in complete accordance withe the explanation that the molecular currents are disturbed by the action of the magnetic field. On the electron theory of metallic conduction, the mechanism of the Hall effect is more obvious, but at present no satisfactory explanation of the reversal found in some metals is known. Further experiments have made it clear that there is a real deflection of the elementary currents, due to the application of the magnetic field, independent of any effect due to strain.

Ohmic and viscous dissipation effects on micropolar non-Newtonian nanofluid Al2O3 flow through a non-Darcy porous media

2022 ◽  
pp. 1-13
Author(s):  
Nabil T. Eldabe ◽  
Mohamed Y. Abou zeid ◽  
Sami M. El Shabouri ◽  
Tarek N. Salama ◽  
Aya M. Ismael
Keyword(s):  
Magnetic Field ◽  
Heat Source ◽  
Numerical Solutions ◽  
Tangential Velocity ◽  
Darcy Number ◽  
Physical Parameters ◽  
Fluid Temperature ◽  
High Concentration ◽  
Ohmic Dissipation ◽  
Similarity Transformations

Inclined uniform magnetic field and mixed convention effects on micropolar non-Newtonian nanofluid Al2O3 flow with heat transfer are studied. The heat source, both viscous and ohmic dissipation and temperature micropolarity properties are considered. We transformed our system of non-linear partial differential equations into ordinary equations by using suitable similarity transformations. These equations are solved by making use of Rung–Kutta–Merson method in a shooting and matching technique. The numerical solutions of the tangential velocity, microtation velocity, temperature and nanoparticle concentration are obtained as functions of the physical parameters of the problem. Moreover, we discussed the effects of these parameters on the numerical solutions and depicted graphically. It is obvious that these parameters control the fluid flow. It is noticed that the tangential velocity magnifies with an increase in the value of Darcy number. Meanwhile, the value of the tangential velocity reduces with the elevation in the value of the magnetic field parameter. On the other hand, the elevation in the value of Brownian motion parameter leads to a reduction in the value of fluid temperature. Furthermore, increasing in the value of heat source parameter makes an enhancement in the value of nanoparticles concentration. The current study has many accomplishments in several scientific areas like medical industry, medicine, and others. Therefore, it represents the depiction of gas or liquid motion over a surface. When particles are moving from areas of high concentration to areas of low concentration.

scholarly journals V. The radio-micrometer

1889 ◽  
Vol 180 ◽  
pp. 159-186 ◽  
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Great Improvement ◽  
Royal Society ◽  
Electric Circuit ◽  
Radiant Heat ◽  
Preliminary Note ◽  
Thermo Electric

In the preliminary note on the Radio-micrometer which I had the honour to present to the Royal Society last year (1887), I promised to complete, as far as I might be able, the development of the instrument, and, in case of any great improvement in the proportions of the parts, to exhibit an instrument in the improved form. In the present paper I have shown how the best sizes of the several parts may be determined, and how the best result may be attained. I must, however, first refer to the fact that on February 5, 1886, M. d’Arsonval showed, at a meeting of the Physical Society of France, an instrument called by him the Thermo-galvanometer, with which mine is in all essential respects identical. The invention of an instrument for measuring radiant heat, in which one junction of a closed thermo-electric circuit suspended in a strong magnetic field is exposed to radiation, is due entirely to M. d’Arsonval, and I need hardly say that it was in ignorance of the fact that he had preceded me that my communication was made to the Royal Society. As soon as I became acquainted with M. d’Arsonval’s work, I took the earliest opportunity of admitting his claim to priority (see ‘Nature,’ vol. 35, p. 549).

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