Author Topic: What is WATER?  (Read 7697 times)

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Re: What is WATER?
« Reply #16 on: September 20, 2008, 11:59:42 am »
So,

We need a circuit that is discharging over and over again a electrostatic charge.....

I know that TEFLON can be charged pretty well..

And a nice website:

http://www.ece.rochester.edu/~jones/demos/kamachi.html


br
steve

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Re: What is WATER?
« Reply #17 on: September 20, 2008, 12:17:15 pm »
more:

Ion or electron beam bombardment can also create electrostatic charge fields, but the most
common and far reaching type of electrostatic charge build up is triboelectric charging. As the prefix
tribo- implies, this charging results from friction or contact between objects.

steve

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Re: What is WATER?
« Reply #18 on: September 20, 2008, 12:22:24 pm »
Dielectric Constant (Relative Permittivity)

Insulator materials are commonly called dielectric materials because all insulators have a
dielectric constant. The dielectric constant determines the ability of the material to become electrically
polarized. There are three types of polarization possible in dielectric materials;
1) Electronic polarization occurs when electrons are displaced relative to the nucleus.
2) Ionic polarization occurs when cations and anions are displaced relative to each
other.
3) Orientation occurs when permanent dipoles, such as H2O are aligned.

Only the low mass bodies of the electrons can polarize in response to very high frequency
electric fields. Ions and permanent dipoles move too slowly and can only be polarized by lower
frequency electric fields. The time needed for a specific polarization to occur is termed the relaxation
time.

Materials with a high dielectric constant have a strong ability to become polarized. The
dielectric constant is equal to the permittivity of the material (?) divided by the permittivity of a pure
vacuum (?o). Permittivity is a proportionality constant that relates the displacement of a charge in
relation to an electric field. Dielectric materials, therefore, have a dielectric constant greater than unity
and are strong supporters of electrostatic fields.
9
Polarization of positive and negative charges presents an electrostatic potential energy that is
associated with opposite charges being held apart from each other. This is the material property that is
exploited in capacitors to create power supplies.

Dielectric Strength
While the dielectric constant determines a materials ability to hold an electrostatic field, a the
dielectric strength of a material is a measure of the material resistance to breakdown. Breakdown of a
dielectric occurs when electrons or holes break molecular bonds in the dielectric medium during and
ESD event creating micro-defects which can propagate through the medium. The units of dielectric
strength are Volts/material thickness which represents the Voltage required to breakdown a certain
thickness of the subject material.

Avalanche
Strong electric fields, such as ESD may free electrons from atoms and accelerate them to
energies high enough to free other electrons from atoms which creates an avalanche of electron
interactions. This is known as dielectric breakdown and the energy required to cause this breakdown is
the dielectric strength. In many instances, the medium between two surfaces in an ESD situation is air,
but in the case of semiconductor devices, the medium could be a thin insulating layer of the device.
Because the electrical field is defined as Voltage per distance, thin layers are particularly susceptible to
breakdown given a particular field strength. This is a major challenge in proceeding toward shrinking
semiconductor device dimensions.


My comment and thoughts: What if what we do by electrolysis is indead freeing electrons and that we indead see a small reaction / avalanche.....All avalanches will end at one place and time.  What if we start to consume those freed electrons? When there are no free floating electrons left, then there will be no covalent bonding / re combining .....


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Re: What is WATER?
« Reply #19 on: September 24, 2008, 00:49:00 am »
New research info:

when the pulse width is within the microsecond range,
the dielectric strength of water remained almost independent of the pulse width. When the pulse
width was decreased to the sub-microsecond range, the dielectric strength started to increase.


hmmmmmmmmmmmmm

br
steve

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Re: What is WATER?
« Reply #20 on: September 24, 2008, 00:56:17 am »
its getting better:

For brief pulses (a few microseconds or less), pure water is an excellent dielectric. However, the water needs to be continually filtered, degassed, and deionized so that it has a resistivity of ~5-7 megohm-cm in order to work reliably as a dielectric in high energy pulsed power pulse systems. For short pulses, water combines high dielectric strength, high dielectric constant (~80), and is "self healing" in the event of an electrical breakdown. These properties allow pulsed power engineers to create compact, high-energy storage and transmission systems using water as the dielectric. For example, water is used as the dielectric in low impedance, high current, high voltage transmission lines that feed 20 million ampere pulses into the center of the huge "Z Machine" at Sandia Laboratory - the world's largest pulse generator - see: http://www.sandia.gov/media/z290.htm and
http://www.sandia.gov/pulspowr/facilities/zaccelerator.html

The main challenge is to keep the water sufficiently pure and keep gas bubbles from forming on the electrodes. Since water is the "universal solvent", it easily becomes contaminated by impurities (dust and ions leaching from the container that increase its conductivity). These impurities must be continually removed since their presence always degrades the water's performance as a high voltage dielectric.

For short pulses, J. C. Martin developed an empirical breakdown scaling relation for water and mineral oil under a uniform E-field over a range of voltages, pulse times, and electrode area based upon his work at Sandia. The relationship is as follows:

F = k*(t^(-1/3))*(A^(-1/10))

where:
F = the peak breakdown field (in megavolts/cm)
t = duration of applied voltage (in microseconds)
A = area (in square cm)
k = 0.3 for water (positive streamers – the normal case)
k = 0.6 for water (a special case where field enhancement is purposely adjusted to cause streamers to form preferentially from the negative electrode instead of the positive electrode)

For example, solving for the positive streamer breakdown field (F) for 1 square cm electrodes in water, stressed by a 1 microsecond pulse in water, we get F = 300 kV/cm. If we used a 100 nsec pulse, this would be expected to increases to 646 kV/cm, and almost 1.4 million volts for a 10 nsec pulse. Breakdown behavior changes with longer (>10 microsecond) pulses, since ionic conduction may begin to alter the E-field distribution within the gap. Considerably more detail can be found in "High Power Switching" by Ihor M. Vitkovitsky, ISBN 0442290675 and “Introduction to High Power Pulse Technology” by S. T. Pai and Qi Zhang, ISBN 9810217145.

Breakdown within water begins as streamers that initiate from points of field enhancements (bubbles, small projections, or particles on the electrodes). As noted above, streamers will form and propagate more easily from the positive electrode in a uniform field. I am not aware of explicit data relating breakdown strength to water temperature. However, increasing the water’s temperature will reduce the water's density and increase ion mobility – these factors may tend to decrease the dielectric strength. Increasing the applied pressure will significantly increase the breakdown voltage, possibly because it makes initial bubble formation (which seems to be necessary for slow streamer formation) more difficult.

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Re: What is WATER?
« Reply #21 on: September 24, 2008, 11:00:08 am »
The second link is already gone!

I hope you saved the web page.

Mikemongo

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Re: What is WATER?
« Reply #22 on: September 24, 2008, 12:35:48 pm »
I do not have that webpage.
Is it not somewere on their website?

br
Steve

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Re: What is WATER?
« Reply #23 on: September 24, 2008, 14:08:22 pm »
I do not have that webpage.
Is it not somewere on their website?

br
Steve

Nope.  I don't know if they just done some website updating, or...

I looked all over their website.  I could have missed it.  There are some pdf  files but I didn't have enough time to look through all of them before I had to come to work.

Mikemongo