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franklyn
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Calcium Carbide and Methylene Chloride ?
We all know that Alkaline and Alkali metals and their salts fizz in
contact with water. The more reactive such as lithium actually produce
a contact explosion. Not so well known is that an Alkali metal in
contact with a chlorinated hydrocarbon such as chloroform or carbon
tetrachloride also explodes. Being hypergolic makes this unsuitable
for anything but a contact initiator for an explosive train.
I have the idea that stable 2 component mixtures using this chemistry
are possible. Calcium carbide dust immersed in a suitable chlorinated
hydrocarbon such as dichloromethane ( methylene chloride ) may remain
metastable and yet with applied activation energy undergo double
replacement. CaC2 + CH2Cl2 -> CaCl2 + CC2H2
Bonds exchanged, unsaturated C2 ionic to 2C covalent, and Cl covalent
to Cl ionic indicates this to have positive heat of formation.
If carbon tetrachloride or ethylene tetrachloride is used instead
and redox is complete, then no gaseous products would be evolved.
This would be similar to the decomposition of cuprous acetylide.
Although that is a molecular compound and therefore detonates, and
my proposed mixture may likely only deflegrate providing a propulsive
impulse rather than a shockwave detonation. This raises an interesting
possibility that this can serve as a firearm propellant which devoid
of muzzle blast would have a low acoustic signiture, eliminating the
need for a muzzle sound suppressor ( so called silencer ).
I have not tried this, where I live precludes experimentation.
[Edited on 30-5-2006 by franklyn]
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12AX7
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| Quote: | Originally posted by franklyn
This raises an interesting possibility that this can serve as a firearm propellant which devoid of muzzle blast would have a low acoustic signiture,
eliminating the need for a muzzle sound suppressor ( so called silencer ). |
Well, no, gas is gas, whatever's pushing the bullet must still be pushing by the time the bullet gets to the end, thus, it's going to push the air
that replaces the bullet when it leaves.
Tim
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franklyn
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Thanks for the comment
| Quote: | Originally posted by 12AX7
gas is gas, thus, it's going to push the air that replaces the bullet when it leaves. |
Most of the sound produced by gunfire is from the free expansion of
high pressure gas from the muzzle, like the whoosh sound made by
the air hose before it attaches to the tire stem. Here, initial impulse
is provided by by the volatilized plasma, which undergoing adiabatic
expansion quickly becomes a liquid and solid aerosol mist similar to
smoke. I propose that the condensed reaction products being non
gaseous only have inertial momentum and will follow the bullet out
of the barrel the way a train follows it's locomotive. Think of the bullet
as having a coiled spring at it's base that ejects the bullet and itself.
A device employing a similar principle has been in the armory of
the US Navy Seals since at least the Vietnam era conflict. A rather
longish 12 gauge shotgun shell houses a malleable steel envelope
in the shape of a condom; this contains the shot. When fired this
assembly is turned inside out propelling the shot but contains the
gas within this now expanded sealed container.
Anyway all of this is just speculation, I am really interested in
feedback and opinions on the chemistry I've outlined, using metal
carbides and chloro carbons, and is it feasible.
.
[Edited on 31-5-2006 by franklyn]
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12AX7
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| Quote: | Originally posted by franklyn
Here, initial impulse is provided by by the volatilized plasma |
Whoa whoa now, pray tell how a chemical reaction produces plasma? Atoms rearranging perhaps, but I haven't heard any evidence of loose ions and
electrons in chemical reactions (a flame isn't conductive, although *supposedly* it can be made conductive with salt vapors).
Tim
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Boomer
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A flame *is* conductive, but not too much at normal temps and pressures (read gas flame). That is how a domestic gas heater senses the flame's
presence, shutting down the gas flow if it goes out. In older days a bimetal was used. Ever wondered why big fires under high voltage transmission
lines are forbidden? 
At higher temps and pressures (read detonation front), conductivity goes way up. That is how VoD is measured today, by *bridging* two insulated wires.
The old method of breaking the wires is less precise for exactly this reason, the hot gasses conduct as well and you cannot know the exact moment the
wire was reached by the det front, since it stops conducting after the front has long passed.
But you are right, this would make a poor propellant. You want the bullet to be pushed all the length of the barrel, accelerating constantly, not just
for the first inch.
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Marvin
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franklyn,
"The more reactive such as lithium actually produce
a contact explosion. "
Lithium is the least reactive alkali metal. It does not produce a contact explosion.
"Not so well known is that an Alkali metal in
contact with a chlorinated hydrocarbon such as chloroform or carbon
tetrachloride also explodes. "
Being in Davis, the facts of the matter are quite well known. The misture is generally stable unless it is exposed to substantial shock but the risk
is high enough that you should never clean an alkali metal with a chlorinated solvent.
"Being hypergolic makes this unsuitable
for anything but a contact initiator for an explosive train. "
No, its not hypergolic either.
"undergoing adiabatic
expansion quickly becomes a liquid and solid aerosol mist similar to
smoke"
Let me get this straight, you reduce the pressure adiabatically and you expect it to turn from gas to liquid to solid under its own force?
Under the circumstances you'd better read the information on aluminium sponge and liquid oxygen and note that allthough the products are solid, it
still explodes (with a massive bang) when used in mining.
Boomer, interestingly I think NASA were trying to use electricity to keep candles lit in space. With no gravity the hot oxygen depleted gasses don't
move away from the flame zone, so they don't stay lit. Using an electric field they could make it circulate and keep it lit.
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franklyn
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Thanks for the feedback Marvin _
Yes you're right, I checked ( One reason for having independent
proof reading , and review ) I had the notion that the smaller
alkali atom is more reactive. Actually Lithium is comparable to
the alkaline metal Calcium in relative fizziness.
I found this reference for carbon tetrachloride material hazards
http://www.intox.org/databank/documents/chemical/carbtetr/ci...
Incompatibility - Materials to Avoid:
ALKALI METALS
(e.g. lithium, potassium, sodium or sodium- potassium
alloy) - form impact sensitive compounds, resulting in weak explosions
with lithium, strong explosions with potassium and sodium, and violent
explosions with sodium-potassium alloy.
ALUMINUM, MAGNESIUM, or ZINC POWDER - mixtures are impact sensitive or
can explode on contact.
< Let me get this straight, you reduce the pressure adiabatically and
< you expect it to turn from gas to liquid to solid under its own force?
Aluminothermite compositions using an oxidizer such as manganese
dioxide can exhibit quite forceful explosion if homogenously ignited.
A stoichiometric mixture of this can only produce solid products.
You are not suggesting that the smoke and dust be collected and
pumped through a heat exchanger before you are willing to call it
a solid are you ?
You're thinking of this as if it is a gas , it is but only at the
temperature of reaction ( at what temperature is atomic carbon a
gas ? at what temperature is calcium chloride a gas ? )
< Under the circumstances you'd better read the information on
< aluminium sponge and liquid oxygen and note that although the
< products are solid, it still explodes (with a massive bang) when
< used in mining.
The aluminum "sponge" is necessary only because even a stoichiometric
mixture of powder would settle. This liquid oxygen explosive is
contrived to be just that, a method to make a bang.
If instead aluminum dust only wet with enough liquid oxygen to fill
the spaces between the particles is homogenously initiated , then
barely any gaseous by product can result, despite an initial violent
expansion. Yes liquid oxygen poured onto a lit charcoal briquette
barbeque can be quite illuminating. I have seen video of this done.
Anyway melting a gun barrel with the first shot is not very usful.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
I recall an article in scientific american , the amature scientist
column , in which someone reversed the usual mode of burning by
introducing instead air or oxygen with a bunsen burner into a
container full of combustible gas.
.
[Edited on 2-6-2006 by franklyn]
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Marvin
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"A stoichiometric mixture of this can only produce solid products."
In a nutshell, this is the flaw in your logic. With Al/O2 the energy of detonation must go somewhere, and its taken away by excess O2. If there is
no excess O2 the reaction will not go to completion and some O2 will still take the energy away. In the shorter term you will have rather more exotic
species in 'gas' form.
It doesn't matter if the energy ends up in the air after products have turned solid and burning has completed, the resulting energy release will still
produce the 'bang', either you make gas products, or in taking away the energy a liquid, solid or gas expands and the result is much the same.
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quicksilver
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| Quote: | Originally posted by franklyn
Although that is a molecular compound and therefore detonates, and
my proposed mixture may likely only deflegrate providing a propulsive
impulse rather than a shockwave detonation. This raises an interesting
possibility that this can serve as a firearm propellant which devoid
of muzzle blast would have a low acoustic signiture, eliminating the
need for a muzzle sound suppressor ( so called silencer ).
] |
I believe I understand where you are going with this concept but it appears that there exists and "apples & oranges" concept here.
When nitric esters are utilized in a firearm they are not detonating in the strict sence of that term but that a controled propulsion is achieved by
controled gas expansion. The entire concept of the proper level of smokeless powder is important so as to avoid detonation. If improperly loaded a
cartridge may detonate but if properly loaded it will propell the bullet down the barrel. Those individuals who load their own ammo know the
detonation issue exists with smokless powder loaded improperly. But such powder is designed to not detonate, per se' if certain elements are
maintained.
The noise is another matter. There exists a device called a muzzel break. It is designed to lessen the recoil of a firearm by redirecting the muzzle
blast and it achieves this reduction at the expense of increase of overall sound. When any material is propelled from the barrel of a firearm the
significant factor is WHERE the gasses go (INCLUDING the air around the projectile). There will always be some form of gas. Back in the 1970's there
was a caseless bullet that was similar to a rocket. It also made noise by the movement of th object in air. Plus anyone who has fired a suppressed
weapon can report to you that the more effective the suppressor, the poorer the accuracy. The gasses from such a piece must follow the flight of the
bullet or you have poor accuracy. Well made "silencers" disperse gas like a muffler on an automobile. In addition that is why a "flash-hider" equipped
weapon is less accurate than one without. And why a barrel "crown" is so very important to accuracy. Ruin a muzzel crown and your accuracy falls into
the toilet.
That being said I imagine it may be possible to propell a bullet in a variety of ways but as soon as the ballistic co-efficient becomes more
achievable, the more sound is recorded from the flight path of same. Therfore the problem is one of trading accuracy for sound. This has been a LONG
term issue in the science of ballistics. A sling-shot's only noise is that of the rubber bands' snapping.....
[Edited on 8-7-2006 by quicksilver]
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franklyn
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Good points.
In my initial post I stated " low signiture ", It seems this
has been taken to mean no sound. Not my goal at all.
It just seems to me that if the propellant has fully
condensed before reaching the end of the barrel that
eliminates the free expansion of gas respnsible for muzzle
blast and commensurately diminishes the sound generated.
As a youngster we inserted lit "ashcan" pyrotechnics into a
heavy steel pipe throwing in rocks after it as an improvised
mortar. It remains with me to this day how attenuated the
sound was made by confining the explosion.
I'm sure everyone is aware that mortars do not make the
ear shattering sound of a howitzer. So the amount and
quality of the gas produced at the muzzle does matter.
Yes I know their velocities are also proportional to their sound.
As it happens only subsonic ammunition can be effectively
suppressed which limits one to less than 1100 fett per second
at the muzzle, before a supersonic boom becomes evident.
This last phenomenon has been used by snipers in the field
to evade detection. The muzzle suppresor ( silencer ) greatly
reduces the initial telltale sound from the muzzle leaving only
the sound of the bullet as it passes by and thereby misdirecting
the attention directly away from the shooters position.
A sound suppression appliance has to be designed as part of the
weapon , ammunition included , as it affects and modifies the
shooting characteristics. It will not necessarilly reduce accuracy.
Kalashnikovs are all made now with slanted muzzles instead of
blunt crowns , these still manage to poke holes in people.
Thanks for the feedback
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enhzflep
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| Quote: |
Originally posted by boomer
A flame *is* conductive, but not too much at normal temps and pressures (read gas flame). That is how a domestic gas heater senses the flame's
presence, shutting down the gas flow if it goes out. In older days a bimetal was used. Ever wondered why big fires under high voltage transmission
lines are forbidden?
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For a simple demonstration of this effect, stick a match to the platter of your microwave using a small lump of blue-tack(sp) or plasticine. Light
match, close door and turn microwave on. It's really quite impressive. You may need to try this a few times as the effect is somewhat finicky. You may
expect balls of flame(?) up to the size of a tennis ball!
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franklyn
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A bit of History
Here we are in the 21st Century
so where are all the rayguns ?
The most common weapon today was invented 65 years ago
by a 21 year old . Read his story attached below.
.
[Edited on 12-7-2006 by franklyn]
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guy
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| Quote: | Originally posted by Marvin
Lithium is the least reactive alkali metal. It does not produce a contact explosion.
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Why does lithium have the largest negative reduction potential out of all the alkali metals yet it is the least reactive? And furthermore why is it
the only alkali metal that will react with nitrogen at room temperature?
[Edited on 7/12/2006 by guy]
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12AX7
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I believe they have the same reason.
Remember that alkali metals want to give up their outermost electrons, actually they don't, in and of themselves -- if they did, you'd never isolate
the metal because it would be emitting copious amounts of electrons as the atoms ionize -- but other elements just so happen to want electrons much
more than the alkalies, so they swipe it, and things sit there, the alkalies kind of upset, the anion slyly content.
So, a lithium atom has a charge of +3, two 1s electrons and one 2s electron. That last electron is going to be roughly 1/3rd of the electric charge,
so in bulk terms, you'll have to convince that lithium to let it go. Hence it takes a reasonable voltage, circa 3V, to get it off. It's also rather
small as an ion or atom, so the electric field is more intese, whatever effect that has.
Compare to cesium, which has a slightly lower voltage, but a much looser electron and larger cloud of other electrons (the missing electron is only
roughly 1/55th of the total charge), so the ionization is easier, and thus the atom is more reactive.
Tim
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guy
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That doesn't make sense becaues if the higher the reduction potential it should be more reactive. And your explanation would make the order look like
this (in order of reduction potentials):
Li>Na>K>Rb>Cs
but it really is
Li>K>Rb>Cs>Na
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Fleaker
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In terms of reduction potentials yes. In terms of reactivity, the first series is correct--why? a variety of reasons many of which previously
discussed.
Remember that reduction potentials are of limited utility at different temperatures.
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guy
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So kinetically the others are more reactive but Li is still a stronger reducing agent.
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Anders2
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Chloroform does not react at room temperature with, or dissolve in, CaC2.
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franklyn
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A reprise of this former post
http://www.sciencemadness.org/talk/viewthread.php?tid=5897#p...
This months Wired features an article on the prolific AK- 47 infantry rifle.
90 years old now , Mikhail Klashnikov is designer of record of what has become
the mainstay of insurgencies and low intensity conflict for the past 60 years.
The first two links tell of it's historical origins as well as a technical overview
http://www.wired.com/magazine/2010/11/ff_ak47
http://www.wired.com/magazine/2010/11/ff_ak47/2
The article closes outlining the turmoil of its turbulent utilization.
http://www.wired.com/magazine/2010/11/ff_ak47/3
http://www.wired.com/magazine/2010/11/ff_ak47/4
.
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AH-Poster
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a quote I found:
"Thus acetylide anions ( R-C≡C:-) can react with alkyl halides such a bromomethane. (CH3-Br) to substitute for the halogen a yield a new alkyne
product"
Also, I was told in an email from a research assistant, who had once worked under George Olah, that he was aware of such an experiment with carbon
tetraiodide with acetylide, and said they were not able to isolate any new crystalline allotrope of carbon because the reaction was not able to be
driven to completion, probably because substituted acetylide ions crystallized into the carbon. The assistant's name was Matthew.
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The WiZard is In
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Quote: Originally posted by quicksilver  |
The noise is another matter. There exists a device called a muzzel break. It is designed to lessen the recoil of a firearm by redirecting the muzzle
blast and it achieves this reduction at the expense of increase of overall sound.
Back in the 1970's there was a caseless bullet that was similar to a rocket.
Ruin a muzzel crown and your accuracy falls into the toilet. |
Muzzle break — Amen when I fire my Styer .50BMG w/ muzzle break - birds fall out of the sky.
There was a rocket firing pistol/rifle the Gyrojet - Google it. I first
laid eyes on one in the gun shop of Abercrombie & Fitch NY in
the early 60's when the gun shop still looked the same as when
TR shopped their before going hunting in Africa. Interesting idea —
except you couldn't hit the side of a barn with one!
Daisy (The BB gun people made the Daisy VR rifle I own one. It
uses caseless .22 ammo ignited by compressed air. When the ATF
declared them to be firearms and not air rifles - production was
stopped. Most interesting 'bout them was the unique way their
cellulose nitrate propellant was manufactured....
Muzzle crown - suppressors screw onto the barrel therefore
crowning is not possible. The muzzle break on my Wby.
.378 DGR and .460 screw onto the barrel therefore crowning
would be possible. If anyone cares I'll take a look latter.
Suppressors also require the use of sub-sonic
ammo to eliminate the crack of the bullet.
[Edited on 6-11-2010 by The WiZard is In]
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franklyn
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A remarkable adaptive behavior many birds exhibit when there is the sound of gunfire ,
correctly associating that with getting shot at , they will dive low. | Quote: Originally posted by The WiZard is In | " the Gyrojet - I first laid eyes on one in the gun shop of Abercrombie & Fitch NY
in the early 60's when the gun shop still looked the same as when TR shopped
their before going hunting in Africa. " |
Gyrojet was featured in the 1964 James Bond film " You Only LIve
Twice ",
used in that as intended , for close quarter combat.
The long defunct Madison & 45th Abercrombie & Fitch just up the street from
what was then the PanAM Building that still had regular helicopter service to
the area airports. I often would go there to peruse 7th floor gun shop after
school and oogle the side by side Purdy's selling then for many thousands ,
those go today for ten times as much. There was even a gun range in the
basement where you could try before you buy. No military motiffs there , if
you wanted a Mannlicher Carcano you had to get it mail order ( pre 1968
Omnibus Crime Control Act ) one still can with a Federal Firearms License.
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quicksilver
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I had a rather amusing daydream for those of us who live in Wyoming, Montana, Arizona, Idaho, etc to have a periodic "convention" for those who live
in the UK, NY, CA, various places in Europe & Common Wealth nations.....to host a convention of sorts where the various different fellows could go
out shooting, hiking, looking a gun stores, blasting supply shops freely. Having an evening of relaxed conversation without fear of someone
"reporting" what you said or fear of misinterpretation..... Just for a few days to get away from the Nanny-State mentality. It would possibly be very
refreshing for many; to not have to lock your car doors all the time.... I know it would never happen; the paranoia's too deep already.
It would be like opening your home to a foreign exchange student.
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hissingnoise
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| Quote: | | It would be like opening your home to a foreign exchange student. |
I don't think anyone this side of the Atlantic wants Sarah Palin anyway near here in any capacity . . .
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Mr. Wizard
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| Quote: Originally posted by hissingnoise | | Quote: | | It would be like opening your home to a foreign exchange student. |
I don't think anyone this side of the Atlantic wants Sarah Palin anyway near here in any capacity . . .
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I didn't realize we had such an august personage on the board, who can speak for all of Europe. Since we have you now, maybe you can tell us what
kind of people you would like to have visit? The great unwashed among us want to know. You Betcha!
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