<bart416>
berndj, bismuth won't melt at room temperature but you can still easily melt it on your kitchen stove
<bart416>
And it's less toxic than lead
<nathan7>
bart416: 'less toxic than lead'
<nathan7>
bart416: well that's reassuring
<bart416>
nathan7, you don't want to rub it along your skin
<bart416>
Or eat it
<bart416>
that's about it
<nathan7>
it's bloody heavy
<bart416>
Yes
<Helldesk>
"Bismuth has unusually low toxicity for a heavy metal." claims the wikipedia article
<Helldesk>
some isotopes of bismuth have potential use in extremely targeted cancer therapy, and then there's pepto-bismol of course
<Helldesk>
with bismuth subsalicylate as the active ingredient
<bart416>
wikipedia probably won't even mention its more fun uses
<lekernel>
there's merbromin too :-)
<lekernel>
with mercury and brome, used as antiseptic for minor cuts
<lekernel>
yay
<bart416>
bismuth also makes for an excellent gamma radiation shield
<bart416>
(It's on par with lead for that)
<bart416>
Stupid NDA >_>
<lekernel>
why isn't it used more often for radiation shielding? more expensive than lead?
<bart416>
It is often used for radiation shielding...
<bart416>
Its also used as a coolant in reactors
<bart416>
(due to its low melting point)
<bart416>
lekernel, uhm ever had a ct?
<lekernel>
ct?
<bart416>
CT scan
<lekernel>
no
<bart416>
That's a place where you'll commonly find it lightweight shielding to limit radiation exposure
<bart416>
Like if they need to take a chest ct they'll often give you a something to shield your neck and belly
<bart416>
That's a place where you'll find bismuth
<bart416>
Fits the bill perfectly
<lekernel>
well, I also visited two nuclear reactors and a nuclear shelter, and took apart an old xray machine, all used lead for shielding :)
<bart416>
Well yeah, lead has better mechanical properties
<nathan7>
Helldesk: what's all this sub-shit?
<azonenberg>
bart416: i just asssumed they were all lead based lol
<nathan7>
leading
<bart416>
azonenberg, they're not
<bart416>
bismuth has only been in use the past 10 years or so though
<bart416>
So old equipment is generally still lead based
<bart416>
bismuth is actually a by product of extracting lead from ores
<bart416>
So they sort of stacked up a pretty big supply throughout the years
<azonenberg>
lol
<bart416>
btw, the soviets have been using it a lot longer
<bart416>
That being said, I'd better shut up about this before 1) I get arrested 2) I get somebody killed due to my BAC being fairly high after a bottle of wine
<bart416>
azonenberg, do you think it'd be viable to power a small railgun with smd capacitors?
<azonenberg>
bart416: Define small :P
<bart416>
Imagine rifle size
<azonenberg>
My immediate thought is no
<azonenberg>
none of them are rated for even close to high voltage
<azonenberg>
with decent capacitance
<bart416>
well, if you use copper tubing it doesn't have to be high voltage though
<XgF>
bart416: copper tubing isn't viable for a 'usable' rail gun
<bart416>
define usable :P
<XgF>
Projectile travels more than 10cm out of the gun before hitting floor :p
<bart416>
Nah you get them to go way further than 10 cm actually :P
<XgF>
Also, you'd want some form of injection system so you don't have to accelerate the projectile from a dead stop
<bart416>
You can't accelerate projectiles from dead stop
<bart416>
I've built enough railguns before XgF :p
<bart416>
And copper tubing isn't nearly as bad as you'd think :S
<bart416>
Obviously solid strips of copper are better
<XgF>
Still, magnetic launchers have efficiency which significantly increases with voltage
<bart416>
The current is important, not the voltage
<bart416>
Worst case scenario I put some capacitors in series to raise the voltage rating eh :P
<XgF>
Indeed, but increased voltage -> increased current for a given rail resistance. Increased voltage also -> significantly denser energy packing in the capacitor bank
<bart416>
that is true
<bart416>
but that's the reason why you'd be using smd in the first place
<bart416>
you can densly pack pcbs
<bart416>
and stack them
<bart416>
+ its far lighter than conventional capacitor banks
<XgF>
True
<XgF>
...Requires experimentation
<XgF>
wishes carbon aerogel capacitors didn't have such high ESRs
<bart416>
best weapon we ever built that used magnets was a few motor stators + lab PSUs + leds + light sensors
<bart416>
We embedded a piece of metal into the wall...
<bart416>
That was in highschool, heh
<bart416>
damn was that teacher pissed
<azonenberg>
lol
<azonenberg>
how deep and what kind of wall?
<XgF>
Do transformers count? I'd say that my flyback generator was "most likely to injure"
<azonenberg>
a foot into concrete vs a quarter inch into sheetrock is a big \delta
<XgF>
...though throwing the PSU transformer at them may be more effective :p
<bart416>
standard european brick wall
<bart416>
was in the air gap of the wall
<XgF>
Wow
<bart416>
rectified 380V 3 phase...
<XgF>
I think its the general rule with magnetic weapons: Unless they're really really big, you may be better of throwing the PSU/caps/whatever at them :p
<XgF>
380V 3 phase? Odd voltage
<bart416>
Not really :S
<bart416>
380V 3 phase is standard in Europe for machines
<XgF>
is used to 415V 3phase
<bart416>
Where do you live?
<XgF>
UK
<bart416>
Yeah but UK has always been using its own system
<XgF>
Aah... former 220V country? 400 would be European harmonised, 415 UK norm, 380 norm for a former 220 country
<bart416>
I've never found 400V RMS on a 3 phase outlet XgF
<bart416>
Always 380-390V
<bart416>
1 phase it's 220-240V
<XgF>
Everythings slightly crazy over here at the moment... all of our distribution equipment has stickers on it warning you that inside you'll find two sets of wiring colours
<bart416>
:S
<XgF>
Old stuff to the old UK standard; new stuff to EU harmonised standard
<bart416>
Here we just slap together what we find of wires except in the fuse box
<bart416>
Cause they actually bother to check that
<bart416>
heh
<bart416>
Everything else, meh just pick what you want
<XgF>
Requires some care; old neutral (black) is now a phase colour
<bart416>
though yellow-green for earth
<bart416>
black is still used for neutral here as far as I know :S
<bart416>
Sometimes blue
<XgF>
At least new neutral is light blue as opposed to old phase plain blue
<bart416>
Phases are usually red-ish tints
<bart416>
Red, Brown, Orange, ...
<bart416>
Seen yellow as well a few times in older machines
<XgF>
Still, if you talk about phases around here, we still think in the old (Red, Yellow, Blue) colours. We care because blue is atatched to the fire alarm system
<bart416>
huh?
<XgF>
Fire alarm goes off -> Blue phase goes off -> PA system goes off -> people can hear the fire alarm
<XgF>
Also, audio stuff tends to get... noisy... if you put it on the same phase as, say, 6 3kW strobes :P
<bart416>
lol
<bart416>
Almost as bad as when we make that CNC lathe at a friend's machine shop spin up to speed >_>
<bart416>
You can see the lights dim, lol
<XgF>
All audio gear goes on blue phase firstly as a anti-noise precaution, secondly because any audio gear which makes noise must go off in event of a fire
<XgF>
...metal bands are notorious for ridiculously loud guitar cabs
<bart416>
Talking about metal bands
<bart416>
Graspop (large metal festival) few years ago
<bart416>
It's a few kilometers away from a nuclear powerplant eh
<bart416>
They had no power :')
<bart416>
Electricity fell out
<XgF>
lol
<XgF>
Festivals tend to run on gen sets
<bart416>
If you turned your head 10° you could see the reactor dome in the background >_>
<bart416>
I doubt they were running on generators that close to a powerplant
<XgF>
Tends to be hard to get ~400A 3-Phase supplies installed into the middle of a field
<XgF>
Hiring out a genset works out cheaper
<bart416>
Nah, the festival is always on the same spot and has been there for so long that they ensured that they can tap off the grid actually
<bart416>
A lot of heavy industry nearby so not much of an issue I guess
<XgF>
'fair enough. I just know that even Glastonbury here runs off gen sets
<bart416>
They had a nice row of fences to prevent people from walking to the transformers actually >_>
<bart416>
Nice thick 380V power cords, a lot of them
<bart416>
Was pretty freaky actually
<bart416>
the camping did run of generators though I think
<XgF>
Probably a set of 5 camlocks per feed :)
<XgF>
powerlocks**
<bart416>
But it's sort of sad if you tap power of the grid
<bart416>
You can see the reactor in the background
<bart416>
And you have no power
<bart416>
It's really just :')
<bart416>
It's priceless actually
<bart416>
But yeah where were we
<XgF>
In the past we've had people get confused because a few of our trips have a time delay before they can be closed again...
<bart416>
Rectified 380V 3 phase makes for an excellent powersource for magnetic weapons
<XgF>
I can imagine. Unfortunately, I don't think I'd get permission to plug into one of our 125A sockets :p
<bart416>
lol
<bart416>
Can't remember how much the current limitation was
<bart416>
Was pretty high
<XgF>
...I think they've brought us up to 5 125A sockets in one of our buildings now (+1 125A breakered at 100A)
<bart416>
:D
<XgF>
I don't know if theres actually capacity to run all of them at once or not, however :p
<bart416>
Well yeah, the highschool had a pretty nice machine park so they actually needed the ability to draw full power on their 3 phase outlets
<bart416>
But now I'd just love to try out some of these things in the motor lab at college now
<bart416>
They tap directly of the high voltage grid
<bart416>
And have their own transformer as far as I know
<XgF>
It's an octagon shaped room... which means that various events want to run in random corners of it
<bart416>
lol
<bart416>
why octagon? :S
<XgF>
Dunno. maybe they decided upon the name "The Octagon Center" and then thought it would be a good shape :p
<XgF>
So practically you're never going to use more than 3 of the sockets (+ the 100A one, since that feeds the dimmer pack)
<bart416>
:D
<bart416>
yay, only 4 more rar files to go and I'll have all elektor things from 1980 till 2010
<XgF>
RAR is a damned inconvinient archive format
<azonenberg>
indeed
<XgF>
Whenever I need to open one, I never have software to do so
<bart416>
I have winrar installed on all my computers so not much of an issue
<XgF>
Installing WinRAR on my Macbook would prove challenging
<bart416>
You deserve to get shot for using a mac anyway
<bart416>
Crappy expensive laptops
<azonenberg>
lol indeed
<XgF>
When I sell it in a couple of years, I'll get back the extra I paid for it, and if anything breaks, I can walk into an Apple store and have them fix it for me that day :p
<bart416>
In college last year "how do I get eagle to work on my macbook????" :|
<azonenberg>
Or you could use a sawzall
<XgF>
Install it
<bart416>
"how do I get this cisco vpn client to work on my macbook?"
<azonenberg>
Never fails to remove the offending mac from your life
<bart416>
"how do I get ... to work on my macbook?"
<bart416>
XgF, do like me
<XgF>
Serves all the roles in my life Linux used to... without every other package coming broken
<XgF>
(...does Bluetooth work on Linux yet? I mean, I had a generic Bluetooth USB dongle and it refused to work)
<azonenberg>
c4-blastingcap i think is the package
<bart416>
But really thinkpads are the best laptops I've ever used
<azonenberg>
it's listed in the recommended packages but isnt installed by default for safety reasons :p
<bart416>
almost impossible to destroy
<bart416>
fast
<bart416>
great hardware support
<bart416>
almost no pre installed crap
<XgF>
Nah. Like every PC laptop, their trackpads are a peice of shit sent from hell
<bart416>
and matte screen!
<bart416>
Yeah but thinkpads have the red dot as mouse :P
<XgF>
That is a flaming peice of shit sent from hell :p
<bart416>
Nah, its awesome
<bart416>
It's for when you're jumping out of an airplane and can't operate the touchpad easily
<XgF>
All laptops should come with multitouch trackpads a standard
<bart416>
You can use the red dot
<bart416>
The thinkpad doesn't need a parachute btw
<bart416>
It has a built in set of rockets to slow down when it nears the ground
<bart416>
Together with an auto deploying airbag
<bart416>
Or something like that
<bart416>
I've seen a thinkpad drop from the astronomy club tower (4 floors high)
<bart416>
onto pretty hard ground
<bart416>
All it said was "powercord unplugged"
<bart416>
xD
<XgF>
My general line of thought was "I need a laptop. It must be Unixy. Linux requires too much fucking around. Every other Unix requires at least as much fucking around as Linux. This leaves me with only one option"
<bart416>
Nah on thinkpads it works smoothly
<XgF>
Linux doesn't work smootly (enough) on anything
<bart416>
On thinkpads it does
<bart416>
Never needed to install any driver
<bart416>
Everything I needed came with the standard debian dvds
<XgF>
If I plug in my phone, it should automatically configure it to work as a cellular modem. If I plug in a Bluetooth dongle, it should enable Bluetooth.
<bart416>
that's peripherals though
<bart416>
That's another subject
<XgF>
...The Bluetooth dongle should work simply, damnit. There is one standard which every USB dongle supports
<bart416>
not really
<bart416>
I've never ever seen any usb device stick to a standard completely
<bart416>
Not even damned usb drives can get it right at times
<XgF>
1nF... not gonna get much energy into them unless in ridiculous bulk
<azonenberg>
Lol yeah
<azonenberg>
you need a few hundred uf
<azonenberg>
at least
<XgF>
I can't get to Farnell BE from here... but I would say that even if you can afford the hundreds of thousands required, they'd probably end up more bulky
<bart416>
well yeah, I'm not looking at going in excess of 200 m/s for this :P
<bart416>
also, wrong link
<bart416>
capacitors I'm looking at are 1uF 100V
<bart416>
still not really sufficient in my opinion
<bart416>
azonenberg, copper plates with titanium dioxide as dielectric
<berndj>
XgF, i find the blue/brown scheme totally crazy compared to red/black
<berndj>
it's like going from 100% intuitive to 30% confusing
<XgF>
berndj: It is colour blind safe
<berndj>
compare blue from single-phase wiring with blue from 3-phase wiring - see a blue wire... which is it!
<XgF>
Same
<XgF>
Blue is always neutral
<XgF>
Brown, Black, Gray (IIRC) are phase
<berndj>
blue is always neutral except when the other wire is brown
<XgF>
Wha? EU harmomisation says blue is always neutral
<berndj>
oh, i guess black is another one then: new 3-phase phase wire or old neutral?
<berndj>
er, i misspoke. blue is always neutral except when the other wires are red and yellow
<XgF>
Well, if you see "Red, yellow, blue, black" you have old standard; "brown, black, grey, light blue" you have new harmonised standard
<azonenberg>
And in the USA black i think is usually hot :P
<azonenberg>
white neutral and green ground
<azonenberg>
(in single phase wiring)
<XgF>
Yes
<berndj>
dunno, but i find the old colours a million times less confusing; granted, i'm not colour-blind, that's a valid argument
<berndj>
yeah, at least green/yellow is universally earth!
<XgF>
wonders when ring mains are going to be dropped from the regs
<berndj>
our appliances are all brown/blue but afaik house wiring is still red/black
<XgF>
They're obsolete
<XgF>
The UK only changed install wiring a few years ago
<berndj>
i think brown/blue house wiring is _allowed_ but not required
<berndj>
damn those europeans and their funny colours!
<XgF>
Also, people seem to like installing ring mains even when a radial would be cheaper. like our kitchen fitter
<berndj>
i was under the impression ring mains were actually _required_ in the uk?
<XgF>
Both sides of the ring run *taped together* behind all our kitchen units. It would have been cheaper to buy one 32A cable
<berndj>
perhaps with emphasis on "were" - past tense
<XgF>
Never required
<berndj>
here ring mains are quasi-strictly verboten
<XgF>
Presumably radials fused at >16A are too?
<XgF>
being as your plugs aren't fused
<berndj>
nope; you're allowed to have up to 20A with socket outlets rated at 17A
<XgF>
OK, up to 20A
<berndj>
our plugs aren't fused, but GFCI has been mandatory for decades
<XgF>
same here
<XgF>
Here I think up to 32A is allowed to sockets
<berndj>
32A... wow
<berndj>
oh, but your plugs are fused
<XgF>
If memory serves me... some engineers carry 125A three phase to 230V british standard plug adaptors to plug their kettle into :p
<XgF>
Not sure on the exact legality of that without intervening circuit breakers
<azonenberg>
In my living room here in the USA we have three 20A circuits
<berndj>
lol @ 125A.  my house breaker is only 60A
<bart416>
On 110V I guess azonenberg ?
<azonenberg>
each one has somewhere between 2 and 4 plates, each with 2x 15A outlets
<azonenberg>
Yes
<bart416>
Urgh :|
<XgF>
berndj: 125A *three phase*. 375A of single phase power :D
<bart416>
Sounds like a damned fire hazard to me :P
<XgF>
Our downstairs, upstairs and kitcheneach have a 32A ring
<azonenberg>
bart416: I spread the load around
<azonenberg>
my server farm is plugged into two or three plates
<azonenberg>
pulling close to 20A in total
<azonenberg>
But i dont think there is anything stopping you from pulling 15 < x < 20 without blowing
<azonenberg>
from one outlet
<berndj>
afaik breakers' rating have 33% slop
<berndj>
so if it says 20A, it's allowed to trip only at up to 26A
<berndj>
err, that's weirdly phrased, hope you guys can parse that
<XgF>
33% rating slop, plus something like +20% for 1 hour or less, on a logarithmic increasing scale (+10% for 2 hours and so on)
<berndj>
and momentary draws way in excess are no problem; 5x overcurrent for even the fastest breakers
<berndj>
i'm still trying to find info on whether "curve 1", "curve 2" etc. are actual standards or just loose manufacturer consensi
<bart416>
Our 380V in the house has 38A breakers
<bart416>
For outside I think it was somewhere around 60A
<bart416>
(outside including toolshed etc...)
<bart416>
Regular 230V has 16A breakers
<XgF>
I think the Student Union building I work in has a 2kA 3phase supply or something equally ridiculous
<berndj>
my PSCC isn't even 2kA
<XgF>
(Yes, it has its own mini substation)
<berndj>
kettle+multimeter+calculator says it's only about 460A :(
<bart416>
lol
<XgF>
But we are talking about a building with something like 9 eateries in it, so it does use a lot of power for cookers and such :p
<berndj>
there's probably something wrong with the supply, i can't believe that the PSCC should be that low
<bart416>
XgF, you should see the distribution boxes in some machine shops
<bart416>
It's nuts
<azonenberg>
bart416: My school has at least two major transformer substations
<bart416>
the manual circuit breakers are just big copper bars with a long handle cause they're certain they'll arc xD
<azonenberg>
But the union doesnt have one ofi ts own
<bart416>
azonenberg, I know of 3
<azonenberg>
Well, one of these two is huge
<bart416>
2 for the mechanical and electrical engineering building
<bart416>
And 1 for the textile engineering building
<azonenberg>
like, multiple 40kV lines running in
<XgF>
Theres another one under the Octagon Center, I think similar current supply. My building (physics department) probably has one. Engineering buildings probably have one each
<azonenberg>
to a few dozen transformers
<XgF>
Being as we are in the middle of a city, they're all underground
<azonenberg>
These two are aboveground
<bart416>
Lab I worked in a few years ago was even more insane
<azonenberg>
There is at least one more underground in the engineering building basement
<bart416>
But yeah, that was to feed that damned synchrotron >_>
<bart416>
The entire basement was filled with equipment for power management
<bart416>
If I would have stolen one of those transformers in some way I would be rich simply cause of the scrap iron I think
<bart416>
Let alone the copper >_>
<azonenberg>
Lol
<XgF>
bart416: You'd probably lose it all again to oil disposal
<bart416>
You can sell the oil as well XgF
<azonenberg>
XgF: If you're stealing equipment you probably dont care about the environment
<azonenberg>
Sewer
<bart416>
That too
<XgF>
azonenberg: depends on how sure you are that the transformer isn't full of something potentially nasty to you :p
<bart416>
XgF,EU regulations won't allow that :P
<bart416>
it's always some sort of synthetic oil that just smells bad
<azonenberg>
XgF: Again, If you're pulling gear out of a live circuit
<XgF>
bart416: Depends on the xformer's age
<bart416>
Except in older transformers
<azonenberg>
I dont think you're that too concerned
<bart416>
That drains into the skin actually
<bart416>
but is non toxic
<bart416>
Just wear gloves
<XgF>
azonenberg: I might know how to kill power to the transformer. I might not know whether it contains something like PCBs
<azonenberg>
True
<azonenberg>
You'll find out in 20 years? :P
<XgF>
We have enough cupboards sealed off with asbestos stickers for me to worry about :p
<bart416>
azonenberg, very few transformers use toxic oil
<XgF>
bart416: Depends upon age, of course. Pre ~1980...
<bart416>
And honnestly in this case I'd be more worried about the device the transformer in question is powering than the transformer itself, heh