Charges at low conductivity

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Revision as of 22:58, 15 November 2008 by BPappas (Talk | contribs) (Lightning)

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Introduction

Ions will associate if they get closer than an energy that corresponds to -kT. <math>\text{ }E_{coul}=\frac{-e^{2}}{4\pi \varepsilon _{r}\varepsilon _{0}d}</math>
In water: <math>\varepsilon _{H_{2}O}\simeq 80\text{ and }d\gg 0.7nm</math>
In oil: <math>\varepsilon _{oil}\simeq 2\text{ and }d\gg 27nm</math>

In oil the electrostatic attraction is longer range than in water. In oil the “solvated” ion must be much larger than in water.


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Oil "Electrolytes"

The micelle core is highly polar. Possibly like a molten salt?
The diameters are 10’s of nanometers.
Single polymer molecules may be sufficient.
InverseMicelle.png


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Creation of charged micelles in oil

Micelles exchange ions with each other and with surfaces.

The equilibrium is a dynamic balance.

Reference


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Creation of charged surfaces in oil

Reference


Reference


Reference

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Electrical double layers in oil

Reference
The electrostatic repulsion is determined by Coulombic forces between the charged particles: <math>\Delta G^{R}=\frac{\pi D\varepsilon _{0}d^{2}\zeta ^{2}}{d+H}</math>


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Lightning

Electric charges at low conductivity!!!


ArtToday.com

There is a great book on preview in Google Books called the Microphysics of Clouds and Precipitation that has a great chapter on cloud electricity.

The section 18.4 of the chapter talks about weakly charged clouds, and how the charges seem to be distributed over the volume of the cloud. One would expect that base of the cloud, since it is a poor conductor, would be negative, while the top would be full of positive ions; this actually ends up not being experimentally true in some cases, though this is not discussed in the book that I could find. Dr. Morrison did mention that depending on the nucleating particles there could be a charge variance in clouds of different geographical regions: has anyone found a reference for this?

The chapter then goes on to discuss the individual particles in the cloud, and how this distribution is varied in thunder clouds versus fair weather clouds. This was an interesting graph about the electric charges on differently sized drops and types of clouds, although not all of the supporting text is available online.

Looking over the book, I feel like the case for clouds being a form of Soft Matter. Does anyone have any thoughts on it?

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Explosion in oil processing

Klinkenberg and van der Minne (1958)
“Early in 1954 a large tank in Shell’s refinery at Pernis exploded 40 minutes after the start of a blending operation in which a tops-naphtha mixture was being pumped into straight-run naphtha...


On the following day …again an explosion occurred 40 minutes …”



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Common Misconceptions on "Static Electricity

For more detailed description go to this website(it's fun to read!): http://www.eskimo.com/~billb/emotor/stmiscon.html

  • 'Static Electricity' is electricity which is static? → No.Electrostatics is not about "staticness," instead it's about charge and forces.
  • Electric circuits have nothing to do with static electricty? → Wrong. Electric currents are caused by voltage, and the voltage in a circuit is caused by the imbalances of charge which are present on the surface of the metal wires. "Static electricity" is what makes circuits operate! Without the "static electricity" supplied by batteries or generators, modern electrical devices could not exist.
  • Friction causes 'static electricity?' → Wrong. Static electricity appears whenever two dissimilar insulating materials are placed into intimate contact and then separated again.
  • 'Static electricity' has nothing to do with High Voltage? → Wrong. Everyday "static electricity" involves immense voltages. The tiniest "static spark" is caused by about 1000 volts. Longer "car door sparks" and "doorknob sparks" can involve as much as 10,000 volts.
  • 'Static electricity' is a buildup of electrons? → Not exactly. It is not a buildup of anything, it is an IMBALANCE between quantities of positive and negative particles which existed beforehand.
  • Neutral objects have no charge? → Not quite. Electric charge is the major component of all atoms. Therefor matter is made out of canceled electric charge.
  • 'Charging' a capacitor fills it with charge? → No. 'Charged' and 'Uncharged' capacitors actually contatain equal amounts of charge.
  • We don't use 'Static electricity,' it's too weak and feeble? → Not exactly.
  • 'Static' is a useless and rare event? → Not really. "Static electricity" is important in many other places besides lightning, photocopiers, and doorknob sparks. For example, your muscles are driven by long-chain molecules which are forced to slide across each other. Also nerves function as tiny capacitors, with charge pumps to electrify them, and ion gates to discharge them.
  • Clouds are charged by rubbing together? → No.
  • Ben Franklin's kite was struck by lightning? → No. He just showed that a kite would collect a tiny bit of electric charge out of the sky during a thunderstorm.
  • Electrostatics" is the study of electricity at rest? → No.


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