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Author: Subject: SA (Ag2C2.AgNO3) - SENSITIVITY TO STATIC DISCHARGE
holmes1880
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[*] posted on 31-7-2011 at 12:13


Ahhhh..no cap, just wires and an aluminum bottle of NG. Humm. How about PGDN instead, that could be interesting. It would be a booster and a blasting cap all in one. I may suggest it to a young experimenter with electrical savvy.

[Edited on 31-7-2011 by holmes1880]




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[*] posted on 31-7-2011 at 12:22


Wizard should have weighed in on this one since it was posted years ago at ye olde alt.eng.explosives newsgroup IIRC. The story went a ball of cotton
compressed in an empty .22 shell and wet with NG could have a piece of coax used as an HV lead and spark gap across its cut end pressed against the NG wetted cotton, with the other operator end of the coax attached to a stun gun
or an auto ignition coil pumped by a CD discharge as a one shot and this
little gadget reportedly would high order on throwing the switch.
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[*] posted on 31-7-2011 at 18:10


This is what I meant when I said people keep 5-10g batches of SA.....in a darn plastic baggie. If that catches a spark, you won't be counting to 10 using fingers on your hands. The picture is a courtesy of "unclefesterscrew1", a pyro on YT. He later switched to LA/mannitral blasting caps.





[Edited on 1-8-2011 by holmes1880]




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[*] posted on 1-8-2011 at 00:42


I would be heavily concerned about static discharges in the picture above.
I really wouldnt mind if the person that made this bag blew his hands off.

Also I am wondering, this SA seems awfully grey, so that must mean that there are more products here than only SA.
It would be really awesome if someone has the time and equipment to actually do a full spectrum analysis of such a batch.
Ill just stick to hammering the fact that I dont really believe in any decent solution as long as there is no actual data of the material that is used.
I bet most people just use calciumcarbide to produce their SA, asking for contaminations, asking for instability and probably for higher risk of static electric accidental detonations, espically in these quantaties.
My own batches never exceeded 1000 mg, which imo exceeds even the risk I would want to take.

Btw Does anyone actually discharge himself before touching explosives, people can carry quite a charge themselves?


[Edited on 1-8-2011 by User]




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[*] posted on 1-8-2011 at 01:57


Quote: Originally posted by holmes1880  
This is what I meant when I said people keep 5-10g batches of SA.....in a darn plastic baggie. If that catches a spark, you won't be counting to 10 using fingers on your hands. The picture is a courtesy of "unclefesterscrew1", a pyro on YT. He later switched to LA/mannitral blasting caps.





[Edited on 1-8-2011 by holmes1880]


This looks like a binary explosive based on Al and not any Ag2C2. AgNO3. As the DS have a whiteish coulor.

To store primary explosive in this way, if its a primary in the zip bag , is for idiots.

Store it under water and DONT believe that its safe because of the water. Water reduces some risks but not all.

The best is to solve the primary, if possible , therefore for example if expermenting with acetone peroxide it should be stored in acetone solution.

On topic,, what about the risks with static AFTER the cap is finnished and the primary is compressed on top of the seconary in an al-capsule.

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[*] posted on 1-8-2011 at 02:32


I know it was SA, because it is a still from a video where the kid was testing out caps with it- he showed it packed in a pen tubing and set off on a piece of wood. Maybe he did add aluminum to it or maybe it was exposed to light or just contaminated.

Water storage would prevent static accidents, but mechanical accidents could still happen. And as far as pressing it inside Al cap, well, I am really not sure if that would make a difference, but I'd expect a static spark to make its way through thin aluminum. Maybe al may help disperse the spark's energy, but that is my speculation.




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[*] posted on 1-8-2011 at 06:57


Often, silver salts like that exposed to UV could discolor that badly. Considering the "manufacturing background" I'd think it was even not that unique. What becomes of it chemically from strong UV exposure is interesting however.

I believe that at certain levels of static there may be few ways of maintaining safety aside from semi-permanent grounding, etc. Frankly I believe that the USBoM had some recommendations but that was from a time when most all was experimental & surety was unconfirmed (refrigeration, etc).

[Edited on 1-8-2011 by quicksilver]




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[*] posted on 1-8-2011 at 07:34


Quote: Originally posted by holmes1880  
I know it was SA, because it is a still from a video where the kid was testing out caps with it- he showed it packed in a pen tubing and set off on a piece of wood. Maybe he did add aluminum to it or maybe it was exposed to light or just contaminated.

Water storage would prevent static accidents, but mechanical accidents could still happen. And as far as pressing it inside Al cap, well, I am really not sure if that would make a difference, but I'd expect a static spark to make its way through thin aluminum. Maybe al may help disperse the spark's energy, but that is my speculation.


1) If its real Ag2C2. AgNO3 in this zip bag this person is insane.
2) The compound Ag2C2. AgNO3 is not that sensitive to light, offcourse direct sun light will be bad. This guy must have done some serius error under synthesis.
3) The primary explosive compressed in an al-tube should be in some kind of Faraday cage and therefore the risk of static to set it off should be very small.
4) How the double salt is compatible with other chemicals, for example mixed with aluminium and a drop of water, is for you to explore and report.



[Edited on 1-8-2011 by KemiRockarFett]
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[*] posted on 1-8-2011 at 08:57


Quote: Originally posted by KemiRockarFett  

*snip
3) The primary explosive compressed in an al-tube should be in some kind of Faraday cage and therefore the risk of static to set it off should be very small.
*snip

[Edited on 1-8-2011 by KemiRockarFett]


I thought this as well, but The Wizard is IN recently pointed out to me that it has no bearing on static. Only em fields.

"Such an enclosure blocks out external non-static electric fields." - wiki

Do you have source of the Faraday's cage phenomenon being used to help reduce the risk of static discharge?




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[*] posted on 1-8-2011 at 09:02


It is rare to have a totally white precipitate with calcium carbide method, I have the same result SA like him even following a perfect synthesis, look like gray as many other people.


http://en.wikipedia.org/wiki/File:Silver_acetylide3.jpg
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[*] posted on 1-8-2011 at 09:08


Quote: Originally posted by EAPyrotox  
It is rare to have a totally white precipitate with calcium carbide method, I have the same result SA like him even following a perfect synthesis, look like gray as many other people.


http://en.wikipedia.org/wiki/File:Silver_acetylide3.jpg


Temperature and ammonut of nitric acid in the maxium 10 % solution of AgNO3 ?
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[*] posted on 1-8-2011 at 09:30


I realize the synthesis at 70 ° C, I use 45ml H2O + 35 ml NO3 (60%). 80ml.
=> the equivalent of 3/4 (60ml) H2O and 1/4 (20ml) NO3 (conc. 100%). 80ml.
with 1gr of pure silver of course.

But the gray precipitate are due to a non-pure acetylene gas.
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[*] posted on 1-8-2011 at 12:49


Quote: Originally posted by EAPyrotox  
I realize the synthesis at 70 ° C, I use 45ml H2O + 35 ml NO3 (60%). 80ml.
=> the equivalent of 3/4 (60ml) H2O and 1/4 (20ml) NO3 (conc. 100%). 80ml.
with 1gr of pure silver of course.

But the gray precipitate are due to a non-pure acetylene gas.


This should be almost okey but first test to increase the temperature to 80-90 degrees C to increase pE. Secondly, if necesarry, increase the nitric konc, but stay well below 10 % weight % ragarding silver nitate or you will , as you know , get the 1:6 compound.
The sulfide and phoshine compounds will not survive when you rise pE , and probably you will end upp with a more whitish product.
Actually you can run with copper containing Ag alloy , common, as the copperacetylide will not form at this conditions.
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[*] posted on 1-8-2011 at 13:00


Quote: Originally posted by Bot0nist  
Quote: Originally posted by KemiRockarFett  

*snip
3) The primary explosive compressed in an al-tube should be in some kind of Faraday cage and therefore the risk of static to set it off should be very small.
*snip

[Edited on 1-8-2011 by KemiRockarFett]


I thought this as well, but The Wizard is IN recently pointed out to me that it has no bearing on static. Only em fields.

"Such an enclosure blocks out external non-static electric fields." - wiki

Do you have source of the Faraday's cage phenomenon being used to help reduce the risk of static discharge?


My reference is that zip bag for electronic components gives ESD protection for the components inside the zip-bag, and therefore i assumed that a blasting cap of metal will work in the same way as charges prefer to be on the outer surface on the so called faradays cage. BUT if I am wrong some heavy physisits on the forum may tell us more.
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[*] posted on 2-8-2011 at 06:59


Quote: Originally posted by KemiRockarFett  
My reference is that zip bag for electronic components gives ESD protection for the components inside the zip-bag, and therefore i assumed that a blasting cap of metal will work in the same way as charges prefer to be on the outer surface on the so called faradays cage. BUT if I am wrong some heavy physisits on the forum may tell us more.
Faraday cages work because mobile charges on the outside surface move, thereby changing their induced field to cancel out any on the inside. When those charges can't move fast enough, you get a failure to shield outside fields. In the case of ESD protection bags, they're not great conductors, but they do bleed off charge difference over a time to prevent electrostatic buildup. A metal can is even better at that. One of the reasons that ammunition primers are pretty insensitive to ESD is exactly because they're inside metal cans.

This isn't the whole story, though. Faraday cages protect against outside electric fields, but not so much ones generated inside the cage. Consider an electric dipole (a pair of separated opposite charges) inside such a can. You will get charge motion on the surface that will cancel that dipole, but only as it appears to the outside. On the inside of the can, there's still an induced electric field.

Why does this matter? Triboelectric and piezoelectric dipoles is why; that's friction and strain. If you've got mechanical motion going on inside a can, you can get internal ESD purely from the fields induce by motion. So you've got to manufacture the primer and formulate its contents with an eye to eliminating such motion: pressing and binders, for example.
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[*] posted on 2-8-2011 at 07:20


Thank you for clearing that up watson.fawkes!



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[*] posted on 2-8-2011 at 08:20


Quote: Originally posted by watson.  
A metal can is even better at that. One of the reasons that ammunition primers are pretty insensitive to ESD is exactly because they're inside metal cans.


Forsooth! Inside metal cans. Where did you get this
gem from?! The closest they get to being in metal cans
is the presence or lighting rods.

Re la Faraday Cage - comparing static electricity and EMF
is like comparing Mamey apples and Mamoncillo fruit, i.e.,
there is none.

The only hazard of EMF is when blasting with long leg wires
for more that you probable want to know 'bout it....
I commend the Institute of Explosives [IME] Safety
Library Publication Nol. 20.

Safety Guide for the Prevention of Radio Frequency Radiation
Hazards in the Use of Commercial Electric Detonators. (Blasting
Caps) [Sigh. I had to pay for a copy years ago ... now you
can DL their entire Safety Library Pubs for free!]

http://www.ime.org/ecommerce/downloads.php

Byda reminds upon my mind. Years ago when Jack Drewes
CEO of American Fireworks News and I visited the Goex black
powder plant, then at Mossic PA. I took notice their fine
collection of telephone poles with lightning rods atop. They also
had a hide on the hillside for employees to take shelter in the
event of a thunderous lightning storm. One of their wheel mills
had gone Kaboom a bit before our visit. I don't remember it
being the result of lighting.

I suffer from the believe the use of sferics meters is not
uncommon at explosives plants.


djh
----
When struck by lightning it almost invariably explodes violently.

On the night of June 30, 1898, a violent storm raged in Belgium accompanied
by many electrical discharges, one of which struck the black powder factory in
Clermont-sur-Meuse An explosion followed immediately. Three buildings with
their contents of about 865 kilograms of black powder in various stages of
preparation were destroyed by the lightning discharge and the accompanying
detonation. There was no loss of lives. In view of the location of the factory in a
deep valley surrounded by high trees, where a stroke of lightning had never
been observed, it was not provided with lightning rods. On examination it was
found that the lightning had first struck a very tall acacia tree and stripped it
entirely of its bark. It then sprang to the belt gearing only a few meters distant
and traversed its entire length, sending secondary discharges into the various
factory buildings. This is the only explanation of the fact that three separate
buildings blew up at the same instant, for only one detonation was heard. After,
this accident the supposition of the protection offered by the high trees was
abandoned and lightning rods were put on all dangerous buildings.**

**Mem. poudr. salp., X, 59; 1899-1900.

Dr. H Brunswig (1909)
Explosives: A Synoptic And Critical Treatment Of The Literature Of The
Subject As Gathered Form Various Sources
Translated and Annotated by
Charles E Munroe and Alton L Kibler
John Willey &B Sons
1912

----------
100 YEARS AGO

Major Jameson was found lying on his face in a field quite dead.

Around him, in a radius of several yards, were his clothes and
boots, which had been torn and scattered about in an
extraordinary manner. The lightning appears to have struck him
on the right side of the head tearing his cap to pieces and
burning his hair off. It then passed inside his collar down the
front of his body and both legs into his boots, which were torn
to pieces, and then passed into the ground, making a hole about
eighteen inches in circumference and three inches deep. His
collar was torn to pieces, the front of his shirt was rent into
ribbons, the jacket and under vest were literally torn to shreds,
and the knickerbockers he was wearing were literally stripped
from him and scattered on the ground. His stockings and
gaiters were similarly torn to pieces, and on the boots the
lightning had a remarkable effect. They were burst open, some
of the brass eyelet holes were torn out, the nails were forced
out, and the soles torn off. The skin had been torn off the
chest, and the right leg was torn and blackened; blood was
issuing from the mouth and right ear. It is difficult to account
for these appalling effects, or to explain why the electric
discharge should produce widely different results upon different
[time permitting I'll hunt down the missing text.]

Nature 9 September 1897
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[*] posted on 2-8-2011 at 10:50


Quote: Originally posted by The WiZard is In  
Forsooth! Inside metal cans.
Wee little metal cans. Surely you, of all folk on this board, can appreciate a bit of language-stretching.
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[*] posted on 4-8-2011 at 07:24


HI,
Anyone have a perfect synthesis for SA with ag, HNO3 method.
I find mine incorrect, What do you think of that?

http://woelen.homescience.net/science/chem/exps/silveracetylide/index.html

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[*] posted on 4-8-2011 at 08:23


Quote: Originally posted by watson.fawkes  
Quote: Originally posted by The WiZard is In  
Forsooth! Inside metal cans.
Wee little metal cans. Surely you, of all folk on this board, can appreciate a bit of language-stretching.


Working on my post-doc in serendipitous discovery ...
have (re)stumbled upon this.

Explosion; Circumstances attending an , in the Press House and
Incorporating Mills, which occurred at the factory of the
Sedgwick Gunpowder Co., Ltd., at Sedgwick, near Kendal,
Westmorland, on June 23, 1906. By Major A. Cooper-Key,
H.M. Inspector of Explosives.
Journal of the Society of Chemical Industry 25 [20] 1067.
November 15 1906

DURING a severe thunderstorm, which passed over the
factory in question, the cake press house and four
incorporating mills exploded. The explosions were
undoubtedly due to lightning, and they all took place at the
same instant, and there would appear to have been at least
three separate strokes from the same flash. Of these three
strokes, viz., those which struck a poplar tree in front of one
of the mills and the copings of another mill respectively,
could not have been due to surging, sideflash, or other
inductive effect, as the material struck was in each case
non-conducting, but it is not impossible that the presshouse
was blown up by an induced spark or flash in the interior of
the building. There is, therefore, evidence of the somewhat
rare phenomenon of a divided flash striking simultaneously
two unprotected' objects nearly 100 yards apart, whilst at
the same moment, a third object, the press house, 40 yards
from the nearer of the other two, and protected by
conductors, was separately exploded either directly or
indirectly by a portion of the same flash. A description is
given of the " cage " system of lightning conductors

recommended by Major Cardew for explosives factories in
South Africa, where thunderstorms are so frequent and
severe. The following modification of that system is
recommended as securing a reasonable degree of safety, in
the case of explosives factories in Great Britain. Two or
more well-earthed conductors should be raised as high as
practicable on poles standing a yard or two away from the
actual building. These should be connected near their upper
terminals by means of barbed-wire cables. The " finials "
should consist of as many points as possible, and all joints
should be made thoroughly good mechanically, and soldered
in addition. If the conductors are actually in contact with the
building, there is an increased risk of a portion of the flash
seeking an alternative path through some metal inside the
building, with disastrous results, many, if not most, building
materials being better conductors than dry air, and,
moreover, sharp bends are not so easily avoided as when
separate poles are used. Internal masses of metal should be
thoroughly well connected to each other and to earth, and
should be situated at as great a distance as practicable from
the conductors. All external metal, such as rain gutters, lead
flashing, iron door plates, &c., should be connected to the
conductors or otherwise thoroughly earthed. The press
house under consideration in the report, was protected by
two conductors of copper tape of the usual weight, one at
each end of the building, connected along the ridge and well
earthed in wet soil. Neither the metal inside the building nor
the pressure feed pipe leading into it from the pump were
connected to earth, and the conductors had not been tested
for nearly three years. Moreover, the copper tapes were
attached to the building instead of being raised on poles
some little distance away. The building was, therefore,
exposed to danger from all the sources mentioned above.

—G. W. McD

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[*] posted on 4-8-2011 at 09:34


The above article (Journal of the Society of Chemical Industry 25 [20] 1067.) sounds similar to the "FARADAY CAGE" used to protect various things (& people) from high level discharge (see Tesla Coils, etc).

~~~~~~~~~

I did a little reading about what level of static electricity it would take to initiate various primaries & this is NOT a simple question to answer. To cut to the chase it could take as little as 1/10 of a joule at 6Kv but the actual number means very little as you all pretty much realize by now.
"Static" electricity means just that. Static means "not moving", at a charged state, capacitance in some thinking. According to US OSHA testing:
As little as 0.2 millijoules may present an ignition hazard; such low spark energy is often below the threshold of human visual and auditory perception.

Typical ignition energies at minimum are:

0.017 mJ for hydrogen
0.2-2 mJ for hydrocarbon vapors
1–50 mJ for fine flammable dust
40–1000 mJ for coarse flammable dust
An interesting feature is that there MAY be little difference between primaries and little differences between primaries and flammable dust for ignition causation (Wiley InterScience & OSHA). So what level may present an ignition potential? It seems that .100 joule & 6kv will do it but what about any lower? Are we still bound to voltage carrier current to arrive as a set number? It appears that we can't say what specifics WILL ignite specifically but we can say that there is a fairly wide field that may encompass this. It appears that the TYPE of primary has less influence than the physical composition (dust). That's perhaps a reason why lead azide (which is often small enough to air float and flash w/ 2um Al are so suitable for this danger).

I believe this may be too dependent on size of particulate, area of particulate (is it floating is air, etc) and area of exposure. It DOES appear that the old idea that "if you can feel it: it will ignite" is false. This, then is a serious cautionary note. You no longer may be dependent on the "feel" of static charge to use as a warning sign.

"Wiki" has some REFERENCES that may be valuable. Yet it seems it might be physical features & not so much the chemical that make up the "seriously sensitive to predictably dangerous" issues.
http://en.wikipedia.org/wiki/Static_electricity




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[*] posted on 4-8-2011 at 10:24


Quote: Originally posted by quicksilver  
The above article (Journal of the Society of Chemical Industry 25 [20] 1067.) sounds similar to the "FARADAY CAGE" used to protect various things (& people) from high level discharge (see Tesla Coils, etc).



Well... the most common use of Faraday's cage is to keep
RF energy out/in, therefore they are completely (very)
sealed to RF. Remember we? Yes! The relationship of frequency
and wavelength.

Granted the frequency/wavelength of DC is zero, however,
in this context this count for naught.

Some have posited the reason static discharge ignites explosives
is mechanical not electrical.

A Heuristic Approach to Spark Ignition of Reactive Solids

http://www.sciencemadness.org/talk/viewthread.php?tid=13719

Page down.

At 19 pages I am not willing to scan this.

Here dobe a FC for sale on eBay.

http://tinyurl.com/3s8ojr8

I am not impressed with it.

The only one I have ever seen/stood next to was ca. 1960
it was v/ well made. All copper/brass.
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[*] posted on 4-8-2011 at 17:27


Particle size is surely critical, no doubt. But that characteristic is mostly linked to the compound itself, no? Lead styphnate:

"Lead styphnate is particularly sensitive to fire and the discharge of static electricity. When dry, it can be readily detonated by static discharges from the human body. The longer and narrower the crystals, the more susceptible lead styphnate is to static electricity." (http://design.caltech.edu/micropropulsion/styphnate.html)

SA is in that same ballpark-easy to ignite, and rather detonate, from flame and is static sensitive. If anyone looked at it under microscope, probably found the crystals in little long needles.




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[*] posted on 5-8-2011 at 06:35


Quote: Originally posted by The WiZard is In  
Well... the most common use of Faraday's cage is to keep
RF energy out/in, therefore they are completely (very)
sealed to RF. Remember we? Yes! The relationship of frequency
and wavelength.

Granted the frequency/wavelength of DC is zero, however,
in this context this count for naught.
This is just plain wrong. The lower the frequency the electric field, the better a Faraday cage shields it. (I should point out that the Wikipedia page on the subject is also wrong.) For any given cage, the best it performs is at DC, that is, in the electrostatic case. The operation of a Faraday cage is based on Gauss's law. Rather than rewrite everything here, I looked up some online references:

Understanding the Faraday Cage
What Is the Physics of Shields for Electromagnetic Fields and Waves?
http://www.suite101.com/content/understanding-the-faraday-cage-a53389

Replicating Faraday's original experiment, which used electrostatic fields and an electroscope:
http://www.juliantrubin.com/bigten/faradaycageexperiments.html
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[*] posted on 5-8-2011 at 06:53


Quote: Originally posted by watson.fawkes  
Quote: Originally posted by The WiZard is In  
Well... the most common use of Faraday's cage is to keep
RF energy out/in, therefore they are completely (very)
sealed to RF. Remember we? Yes! The relationship of frequency
and wavelength.

Granted the frequency/wavelength of DC is zero, however,
in this context this count for naught.


This is just plain wrong. The lower the frequency the electric
field, the better a Faraday cage shields it. (I should point out
that the Wikipedia page on the subject is also wrong.) For any
given cage, the best it performs is at DC, that is, in the
electrostatic case. The operation of a Faraday cage is based on
Gauss's law. Rather than rewrite everything here, I looked up
some online references:


You created an answer/criticism for something I did not say/imply.

Actually you are agreeing with me! What I said was
(remembering basic physics - the relationship between
frequency and wavelength) the higher the frequency the
shorter the wavelength, making shielding more difficult. And as
I noted — the frequency/wavelength of DC being zero has no meaning here.

[Edited on 5-8-2011 by The WiZard is In]
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