Folks be all blowed up in Boston... - Page 5 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Current Events, News, Politics Keep the politics here.

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 04-17-2013, 08:40 PM   #81
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,132
Total Cats: 187
Default

Quote:
Originally Posted by JasonC SBB View Post
What happened to the main vent?
Clogged by the cordite...
fooger03 is offline   Reply With Quote
Old 04-17-2013, 08:41 PM   #82
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by JasonC SBB View Post
Pressure cookers will hold more active material than the average pipe.
Yes, and that's where my knowledge of the physics of combustion really starts to become inadequate- how to judge the relative merits of a large volume of material in a vessel with a low bursting strength vs. a small volume of material in a vessel with a high strength.


Consider the most extreme possible examples. You could pour five pounds of powder out onto a wooden table, and then throw a lit match at it. The powder would vary rapidly deflagrate, producing a large amount of heat and light, and a large volume of gas. But because the powder is not contained, it would not produce any significant pressure wave. There would be no explosion, apart from some charring due to the heat of the combustion of the powder, the table would be essentially unharmed, as would any objects which happened to be sitting on the table next to the powder.

Now, at the other end of the spectrum, say that you take two ounces of that same powder and pour it into an oblong iron container shaped like a MkII fragmentation grenade of the sort used by the US Army during all of the major conflicts of the mid 20th century.



If you ignite the powder inside of that container, it will cause the pressure inside of the container to increase rapidly and to a very high level, until the container itself yields. When this occurs, there will be an extremely violent release of pressure into the surrounding environment, creating a blast wave which is capable of inflicting percussive injury in addition to propelling fragments of the container at velocities comparable to that of a bullet and capable of inflicting serious wounds in soft tissue.


Between these two extremes lies a continuum of outcomes, in which the volume of the propellant and the design of the container play a give-or-take battle to produce outcomes which vary from *foof* all the way to *BOOM*.


To my admittedly inexperienced mind, a pressure cooker seems like such a weak vessel that a very large volume of low-order propellant combusting inside of it would produce an outcome which is closer to the 5 lbs of powder on the table, as compared to the much stronger pipe containing a smaller amount of propellant, which would seem to be closer to the MkII grenade.






Quote:
I reckon their safety vents aren't an issue for bomb making purposes because they won't flow fast enough to reduce the explosiveness.
Yeah, the vent is as irrelevant here as trying to bail out the Titanic with a teaspoon. It's the overall structure of the thing which makes no sense to me, including the interface of the lid to the pot.
Attached Thumbnails
Folks be all blowed up in Boston...-grenade.jpg  
Joe Perez is offline   Reply With Quote
Old 04-17-2013, 09:02 PM   #83
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 5,684
Total Cats: 555
Default

The "pressure cookers", or the remains of them shown on TV and news outlets seem pretty wimpy. Paper thin, stamped steel. My mom's cooker is cast aluminum, and probably close to 1/4" thick. The lid locks on with interlocking rings, similar to a large caliber artillery breach. The vent/regulator is a tube sticking up the middle of the lid, with a weight that fits over it. It hisses and rattles like a demon.

It also has this 1/2" black rubber plug off to one side. After 40+ years, that rubber plug is as hard as a rock. I'm sure it would explode with quite some force if the main vent/regulator thingy failed.
rleete is offline   Reply With Quote
Old 04-17-2013, 09:10 PM   #84
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,132
Total Cats: 187
Default

Consider that you don't always need a pressure vessel to produce a violent explosion...

RDX and PETN come to mind.

RDX and PETN do not need any sort of pressure vessel to be deadly in small quantities.

Quite the contrary; once an explosion is initiated in RDX, the combustion of the remainder of the material happens so quickly that the time to ignite it all is effectively zero - basically combustion occurs at the speed of sound, but because the initial blast has packed the immediately surrounding material so densely, the speed of sound through the now densely packed material approaches what is practically infinity for our purposes, so instead of requiring a pressure vessel to force homogenous propogation of the explosive, it simply requires a strong and capable ignition source - such as a blasting cap. Blasting caps can fit inside of a mcdonalds drink straw, and are about 3.5 inches long. Electric blasting caps are very sensitive, and can possibly be ignited with the voltage required to activate the "ring" speaker on a nokia 6700.

Put 1.25 lbs of RDX, a Blasting Cap, and a pay-as-you-go cell phone into a pressure cooker, and what do you have?.....


....Room for another 5 lbs of RDX...if it's a small pressure cooker.



Lucky for us, it seems that the pressure cooker bomber didn't have access to RDX, or the more potent PETN. A single 1.25 lb. block of RDX (Or the name you're more familiar with: C-4) would have probably caused greater damage measured on an order of magnitudes of the actual blast....without any additional shrapnel involved. I have cut large steel I-Beams with nothing more than a few correctly placed open-air half-pound blocks of RDX.
fooger03 is offline   Reply With Quote
Old 04-17-2013, 09:51 PM   #85
Elite Member
iTrader: (21)
 
Join Date: Jun 2007
Location: Rochester, NY
Posts: 5,684
Total Cats: 555
Default

Yeah, everyone has a couple of blocks of C-4 just laying around.
rleete is offline   Reply With Quote
Old 04-17-2013, 10:18 PM   #86
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by rleete View Post
The "pressure cookers", or the remains of them shown on TV and news outlets seem pretty wimpy. Paper thin, stamped steel.
Yup.

My grandmother used to have a pressure cooker which sounds like the one you describe. It was made from the melted-down remnants of a Soviet tank, and the fastening mechanism of the lid was the inspiration for the design of the breech in the 16"/50 caliber Mark 7 cannon used aboard the Iowa-class battleships.



Quote:
Originally Posted by fooger03 View Post
Consider that you don't always need a pressure vessel to produce a violent explosion...

RDX and PETN come to mind.
That was exactly my point in post #68, wherein I posited to myself "Well, what if I'm wrong in that fundamental assumption? If a high-order explosive such as TNT or RDX or even something like ANFO were used, then the container of the device becomes less an active agent in determining its yield than simply a thing to put the explosive agent in and provide an affordance for packing shrapnel around."

In a situation in which the supplies used to make the device are supplied by a state, or by a quasi-military organization with access to basic demolition equipment, such a scenario would be easily rationalized.

But it seems to me that most of the contemporary literature indicates the use of low-order explosives / propellants.

And for that, you need a strong casing in order to transform a simple deflagration into an actual explosion.
Joe Perez is offline   Reply With Quote
Old 04-18-2013, 09:40 AM   #87
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Somebody set us up the bomb:

Obama Cut Domestic Bomb Prevention Budget by 45%

Quote:
The Obama Administration cut the budget for domestic bomb prevention by 45%, according to former Homeland Security Assistant Secretary for Infrastructure Protection Robert Liscouski.

Coincidence? You decide.
Braineack is offline   Reply With Quote
Old 04-18-2013, 09:43 AM   #88
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

crazy, the people on gawker were on the right track I guess:

Authorities circulate photos of two men spotted carrying bags in vicinity of Boston Marathon bombings - NYPOST.com



Sorry liberals, they aren't white.
Attached Thumbnails
Folks be all blowed up in Boston...-suspect-525x415.jpg  
Braineack is offline   Reply With Quote
Old 04-18-2013, 09:46 AM   #89
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

IT WAS JOEP!!!!!!!!!!


Attached Thumbnails
Folks be all blowed up in Boston...-article-2310200-19555e16000005dc-515_470x423.jpg  
Braineack is offline   Reply With Quote
Old 04-18-2013, 10:04 AM   #90
Elite Member
iTrader: (2)
 
Join Date: Aug 2012
Location: Indianapolis
Posts: 3,325
Total Cats: 235
Default

Quote:
Originally Posted by Braineack View Post
Somebody set us up the bomb:

Obama Cut Domestic Bomb Prevention Budget by 45%




Coincidence? You decide.
Wait I'm confused, are bomb prevention measures dumb because we can't legislate evil or is Obama dumb for cutting bomb prevention measures?
thenuge26 is offline   Reply With Quote
Old 04-18-2013, 10:19 AM   #91
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

domestic bomb prevention assumes the gov't actually performing one of its only enumerated powers; protecting the homeland.

cutting spending to this department suggests obama is a right-wing neo-**** extremist who helped facilitate the Boston Bombing.
Braineack is offline   Reply With Quote
Old 04-18-2013, 10:34 AM   #92
Elite Member
iTrader: (2)
 
Join Date: Jun 2009
Location: Istanbul, Turkey
Posts: 2,050
Total Cats: 433
Default

Godless Commie is offline   Reply With Quote
Old 04-18-2013, 11:45 AM   #93
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by Braineack View Post
There's a part of me that wants to head over to Endless-Sphere right now and make a joke about how this proves just how dangerous Tenergy LiPo cells really are.

(Cliffs: they have a history of exploding.)

However that particular cell is NiMh, not LiPo.
Joe Perez is offline   Reply With Quote
Old 04-18-2013, 02:21 PM   #94
Boost Pope
Thread Starter
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

I did a little research, and it appears that the cell shown in the picture is from a 7.2v 3000Mah battery pack intended for use with RC cars. You can buy it from Fry's for $18:

Frys.com: Tenergy 7.2V RC Car Battery



I'm sure it's also available from numerous RC Hobby shops as well. Seems to be a pretty common design.


FWIW, NiMh batteries aren't very common on e-bikes. People who care about life use LiMn or LiFe, people who are insane use LiCo polymer, and cheapskates who have given up on being cool use SLA.
Attached Thumbnails
Folks be all blowed up in Boston...-6467992.01.prod.jpg  
Joe Perez is offline   Reply With Quote
Old 04-18-2013, 02:38 PM   #95
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

you know too much. i didnt see a hawaiian shirt in the crowd shots, you clever man.
Braineack is offline   Reply With Quote
Old 04-18-2013, 02:43 PM   #96
Elite Member
iTrader: (6)
 
blaen99's Avatar
 
Join Date: Sep 2010
Location: Seattle, WA
Posts: 4,112
Total Cats: 27
Default

Quote:
Originally Posted by Braineack View Post
domestic bomb prevention assumes the gov't actually performing one of its only enumerated powers; protecting the homeland.

cutting spending to this department suggests obama is a right-wing neo-**** extremist who helped facilitate the Boston Bombing.
To the best of my knowledge, only one party is making a platform on budget cutting.

Smells like the Sequester issue again - try to pin the blame on someone else.
blaen99 is offline   Reply With Quote
Old 04-18-2013, 02:53 PM   #97
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

Traditionally there's one party doesn't want to cut defense spending.

Traditionally there's one party that wants to outlaw defense spending.


My post was 80% a joke.


I also accused JoeP of being a murderer... did it smell of sarcasm to you?
Braineack is offline   Reply With Quote
Old 04-18-2013, 02:53 PM   #98
Senior Member
iTrader: (2)
 
Join Date: May 2010
Location: Beckley, WV
Posts: 868
Total Cats: 36
Default

Quote:
Originally Posted by Braineack View Post
crazy, the people on gawker were on the right track I guess:

Authorities circulate photos of two men spotted carrying bags in vicinity of Boston Marathon bombings - NYPOST.com



Sorry liberals, they aren't white.
Then of course you have the conspiracy theorists saying these 2 guys are Government agents. The guy in the hat with the white symbol is the punisher symbol, which is also the symbol for the late Chris Kyle (former US Navy Seal sniper)



Hat seen here on Chris Kyle himself: (not saying it is CHris in the above photo, you can order these hats)


So I wouldn't say its the end of them trying to pin it on a "Right wing extremist group"
Attached Thumbnails
Folks be all blowed up in Boston...-180413photo1.jpg  
Tekel is offline   Reply With Quote
Old 04-18-2013, 02:56 PM   #99
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

right-wing neo-**** group.

get it right. I've heard that term used in the media at least 5 times now.
Braineack is offline   Reply With Quote
Old 04-18-2013, 03:18 PM   #100
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,860
Total Cats: 1,788
Default

here's some theory for you:


Braineack is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
In need of base map for stock 1997 brandonbkd MEGAsquirt 0 09-29-2015 12:52 AM
Replacing one tire nigelt Wheels and Tires 7 09-22-2015 01:32 PM
Old guy buys old Miata b&t Meet and Greet 3 09-22-2015 10:32 AM
Bp5a swap NA8 Will_da_beast Engine Performance 1 09-14-2015 08:06 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:17 PM.